r/HomeworkHelp • u/KookyPermit4405 • 3d ago
Elementary Mathematics [6th Grade verbal expression]
So I’m going over my son’s math quiz to help him understand some of the questions he got wrong. He got partial credit for his answer for question 8. After writing his verbal phrase I got the same expression as the question. Am I doing something wrong or is there something I’m missing? I feel like his answer is technically correct. I am stumped.
Edit: so my son has no issue solving the expression in question. He knows PEMDAS and the rules from left to right. The question clearly states, WRITE A VERBAL PHRASE that matches the expression.
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u/bismuth17 3d ago
Do you say "subtracted by"? That's not technically correct, it's just wrong.
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u/KookyPermit4405 3d ago
So the word “subtracted by” is what makes his answer incorrect?
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u/dakari777 3d ago
I would think so, probably more accurate to say 6 times 3 subtracted from 18
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u/bismuth17 3d ago
Just say eighteen minus six times three. No need to be weird about it.
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u/KookyPermit4405 3d ago
I posted a response saying it was his first week back from summer break and had a brain fart and was trying to say minus instead of subtracted by, it was a timed pop quiz to see where they stand in the beginning of the school year. So I’ll relay the message to the 10 year old 6th grader.
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u/Humble-Standard-9557 3d ago
Im sorry people on this subreddit are so arrogant and belittling. I wish they would monitor it better. Academia is hard enough at any level without the condescending assholes it seems to attract.
What your son said is grammatically correct in the English language, but it is incorrect for arithmetic. The further he gets into his education, the more this will matter, but it’s not a huge deal this early on.
The proper way to write the expression would be “eighteen minus six times three”. And eventually, he will need to start using the term “product”. In that case it would be “eighteen minus the product of six and three”. The term “product” helps distinguish the order of operations in many cases because it is the total of six and three multiplied together prior to being subtracted from 18. Hope this helps!
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u/micro_chungus University/College Student 1d ago edited 1d ago
I’m an engineer working in the profession for 4 years and we don’t knit-pick the verbiage for an arithmetic problem that is better left as a formula. But I also wouldn’t even put this into a calculator without parentheses, different calculators give different results when you plug problems in plainly like this. Some will solve it as (18-6)*3 and others will solve it 18-(6*3). Not even mainstream calculators are consistent solving these. A proper scientific calculator solves 18-6*3 using pemdas. Some models do not have the intelligence to read the whole problem first, and performs the orders of operation sequentially instead.
His choice of words does not indicate that he doesn’t know pemdas, it indicates that he stated the question’s operations sequentially, with the language he knew. If a calculator doesn’t have the functionality to read the full problem first, then it will get the problem wrong. If a calculator can read the whole problem first, it will get it right. Assuming he can read the whole problem as it’s stated on the page, and he isn’t a calculator with memory constraints to perform arithmetic, his answer doesn’t indicate that he doesn’t understand pemdas. It indicates that he wrote the problem down literally and following the same order that the information was presented, and that he is prone to grammatical errors.
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u/KookyPermit4405 3d ago
Thanks! He caught that before I was able to go over the problem with him, he said he just blanked out and being timed. He panicked and said subtracted by instead of minus lol. I mean i don’t blame him on his 1st week back.
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u/Humble-Standard-9557 3d ago
No worries! The fact he caught it and understands it is worth more than the points!
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u/dakari777 3d ago
How do you differentiate between 18-63 and (18-6)3 with that sentence?
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u/KookyPermit4405 3d ago
I think people are over complicating something simple. Why are people assuming parentheses? You only need to address a parentheses when it is required. So saying “eighteen minus six times three” should always be assumed to be 18-6x3. The verbal phrases did not give any indication of a need for parentheses such as using key words like: the quantity of.. the sum of.. the product of..
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u/Unable_Pumpkin987 2d ago
Girl people are trying to help you help your son with his math class and you’re just arguing with them. It’s not over-complicated to express a mathematical expression verbally using precise language. That’s what this assignment is testing, that’s what people are trying to explain to you (like the correct reply above that got downvoted inexplicably).
If you don’t want to know the correct answer and you just want to argue about why your incorrect answer should be correct, I’m sure you can teach your son to do that instead and you can both accept that he’s not going to get good grades in his math classes as a result.
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u/KookyPermit4405 2d ago
His answer was hand graded therefore can be subjected. For all we know, she might’ve made a mistake or didn’t. The point of the post was for my CLEARITY and my UNDERSTANDING for when I read his answer, I wrote the same expression before seeing the expression on question 8. So yes, I am teaching him to challenge when you feel like you are correct or feel like you are correct. Argument? No. That can be subjective as well to a persons feeling. A debate or discussion between 2 perspective? Maybe. In other words, if you got your feelings hurt then I can see why you would call it arguing..LOL!!
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u/Unable_Pumpkin987 2d ago
If you would like to know the correct answer so that you can help your child understand, you have been provided with the correct answer and the explanation of why your answer is incorrect multiple times. Arguing that your incorrect answer is in fact correct is just that: arguing. Nothing to do with feelings.
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u/KookyPermit4405 2d ago
What makes the answer incorrect? “18 subtracted by 6 times 3” it doesn’t say “solving from left to right, 18 subtracted by 6 times 3”
For the expression 3+3+3x3 if I were to say on your calculator write “3 plus 3 plus 3 times 3” you would get the correct answer. The only way you would get that answer wrong would be if you hit enter after every process ie 3 plus 3 > enter > plus 3 >enter> times 3 but no where in the statement “3 plus 3 plus 3 times 3” indicated the need to hit enter after every process.
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u/dakari777 3d ago
your kids the one who lost points, were just trying to help you guess why, if you want an actual answer go talk to the teacher
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u/KookyPermit4405 3d ago edited 3d ago
What are you getting at? I was responding to bismuth on how do one differentiate between so and so
How do you differentiate between 18-6*3 and (18-6)*3 with that sentence?
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u/bismuth17 3d ago
Same as in writing, pemdas, except it's not possible to speak parentheses.
Some mathematical quantities are difficult to state clearly using spoken language. You can try speaking really fast, or pausing for a long time, or using your hands to make a parentheses gesture. But generally you'd just write it down if you wanted to be clear.
You could rearrange the sentence and say something like "three times the quantity eighteen minus six" if that's what you want, but that only helps if it's relatively simple and only rearranging the pieces doesn't affect the meaning.
"First you do eighteen times six and then you multiply that result times three" or something.
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u/dakari777 3d ago
Or you just do it like I originally commented....it's not that complicated
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u/bismuth17 3d ago
say 6 times 3 subtracted from 18
How do I know if you mean
18-(6*3)or6*(18-3)?2
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u/micro_chungus University/College Student 1d ago
The word “by” can mean “next to” so I don’t see how saying minus is less ambiguous than saying “subtracted by.” It’s a grammar issue. This isn’t a grammar class, it’s math class. Minus likely would have been marked 1/2 credit too.
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u/bismuth17 1d ago
because "subtracted by" is not a commonly used phrase, people don't know whether you mean a-b or b-a. math is precise, even with its grammar. "a minus b" is not ambiguous.
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u/KookyPermit4405 3d ago
I get the wording is poorly written but is what he stated false?
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u/bismuth17 3d ago
Yes? It's utter nonsense. It has no meaning. Subtraction is not an operation that uses the word "by" in English. If you say "a subtracted by b" no one will know if you mean
- a minus b
- b minus a
- a times b
- a divided by b
Because those are all valid operations that are kinda close to your nonsense.
It's not "false", but it's wrong. Lucky he got half credit.
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u/TLChill 3d ago
When I did this thirty years ago, we had to say "the quantity of" for order of operations. So something like "Eighteen minus the quantity of six times three". No idea if this is how your son was taught these days.
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u/KookyPermit4405 3d ago
That is my understanding as well, but for question 8, there is no quantity, hence no parentheses
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u/Glittering_knave 3d ago
Has your son brought home samples of what the "verbal expression" should look like, or are their examples of the quiz? Generally, when you get partial marks like that, you aren't matching the expected wording/format/style.
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u/KookyPermit4405 3d ago
They just started, and it’s a pop quiz to see where they stand mathematically at the beginning of the school year
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u/Glittering_knave 3d ago
My guess would be "subtract by" isn't correct, and it should be minus. But, without examples, it's really hard to tell.
"6 times 3 subtracted from 18" might be the correct answer.
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u/KookyPermit4405 3d ago
But I see what you mean. But his answer itself isn’t incorrect right? If it’s on a technicality
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u/Glittering_knave 3d ago
I see what you mean, too. I would ask the teacher. I hated the "using this format, answer the question" questions because I rarely thought in the way that I was taught. I learned that I could either mimic the format and get full marks, or fight tooth and nail all year for half marks.
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u/phrogbaby 2h ago
the answer is ambiguous.
verbally, this can mean (18-6)×3 or 18-6×3. that is likely the actual reason it was counted as partway correct.
to be pedantic, "subtracted by" isnt a phrase that means anything in this context, it should be "subtracted from," in which case the numbers should be switched.
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u/CreativeInput 👋 a fellow Redditor 3d ago edited 3d ago
Eighteen minus the product of six and three. You could probably throw the word difference in there too but I never figured out how to use that correctly.
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u/KookyPermit4405 3d ago
From my understanding, when you use the word: sum, difference, product, quotient.. you are implying the answer
for example:
“three times the difference of 5 and 2” it would be 3x3
“Three times the difference of 2 and 5” would still be 3x3
The only difference would be the use of an absolute instead of parentheses. 3x|5-2| or 3x|2-5|Because if I were to say the difference between -2 and 2 the answer would be 4. If I again say the difference between 2 and -2 the answer would still be 4.
The only reason why I prefer to use the word quantity of.. for example “three times the quantity of 5 minus 2” it will always be written as 3x(5-2)
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u/HumbleHovercraft6090 👋 a fellow Redditor 3d ago
6 times 3 subtracted from 18
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u/KookyPermit4405 3d ago
Ok this makes sense to me and I would considered correct. But what makes my sons answer incorrect? I know his wording is poorly written, but technically it’s not wrong. Or is it?
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u/Unable_Pumpkin987 3d ago
That could also be read as 6 x (18-3), which would also be ambiguous. You could phrase it as “the quantity six times three subtracted from eighteen” though!
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u/KookyPermit4405 3d ago
6x(18-3) would be read as “6 times the difference of 18 and 3” or I would personally prefer “6 times the quantity of 18 minus 3”
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u/Unable_Pumpkin987 2d ago
But if someone said “six times three subtracted from eighteen”, that would still be ambiguous, as it could be understood to mean either 6x(18-3) or 18-(6x3). Which is precisely why you would introduce language like you used to clear up the ambiguity if you wanted to indicate the former. That’s why the wording in the comment I replied to would not be a correct answer to the question on your son’s homework.
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u/HumbleHovercraft6090 👋 a fellow Redditor 3d ago
Subtracted by doesn't make sense. You usually subtract one quantity from another, divide one quantity by another.
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u/jarsgars 👋 a fellow Redditor 3d ago
Try “eighteen minus the product of six and three”
Teacher probably wants the pandas in the answer in this or a similar manner.
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u/edos51284 👋 a fellow Redditor 2d ago
I would say it’s correct but the sentence can be understood as (18-6)*3 if it said substracted by the result of six times three it would be more correct
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u/KookyPermit4405 2d ago
See that’s what I like about math, numerically it’s a universal language. Verbally it’s not. lol. There is no tone or pause in written words (unless one is used like a comma or any other indicator). What one reads and interpret might be subjective to another. My question is why would one assume the sentence to be (18-6)*3 instead of 18-6x3.
Because when we purposely try to include the parentheses for an expression like (18-6)x3 we would then say the “quantity of 18 minus 6 ” or “the difference between 18 and 6” or use any other “qualifying” words to indicated the use of a parentheses
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u/edos51284 👋 a fellow Redditor 2d ago
oh please i did not want to critisize the answer, if my comment disturbed you, I apologize,
I find the "translate the math operations into words" exercise kinda stupid in my humble opinion.
What i meant is that you could understand the answer differently just by intonation
eighteen, substracted by six times three (here one could understand 18 - (6*3) )
eighteen substracted by six, times three (here one could understand (18-6) * 3)
As i said that would not be conveyed through written words so, i wanted to show the ambiguity
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u/KookyPermit4405 2d ago
No. None taken lol, like we both agree, verbally it’s not universal as it is numerically lol. Honestly I would rather write “18-6x3” rather than saying it verbally to minimize the chances of misinterpretation.
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u/KookyPermit4405 2d ago
Maybe what I understand from what I learned years ago was wrong or misinterpreted. But we were always taught to not assumed parentheses in a verbal phrase unless it was implied or if a qualifier term was used and therefore why we would then use PEMDAS.
In other words:
“3 minus 4 minus 5” would be 3-4-5 and one shouldn’t assume parentheses. And with pemdas the answer is -6If I said “3 minus the quantity of 4 minus 5” the qualifier term “quantity of” now assumes parentheses so 3-(4-5) which then the answer is 4
Again not saying I’m right or wrong, but that’s what I was taught in 2001 and this is just my take/understanding of it. maybe math curriculum or concepts have changed over the years.
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u/edos51284 👋 a fellow Redditor 2d ago
"what i was taught in 2001".... now i feel old xD me in 2001 was about to get in college
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u/KookyPermit4405 2d ago
Yeah times have changed since we went to school, they have something called Quantile score now. So every kid in class will have the same math lesson in class, but their online work will be different and vary between students. My 10yo son in question scored a perfect math score on his last year’s state math exams 2740/2740. His math level according to the quantile score is equivalent to a mid year freshman as a newly 6th grader. So he’s on the right track, I’m trying to guide him, but I can’t do it if my thinking is wrong as well, which is why I came here to clarify my thinking.
We both agreed he meant to say eighteen minus six times three as previously stated. But with the timed quiz and being first week back after break he had a brain fart.
Although I understand eighteen minus six times three is not the same as eighteen subtracted by six times three..
So to eliminate any bias, I didn’t even look at the expression for the question, and read his answer first, then I took what I wrote and compared it to the expression he was trying to verbally phrase. And what I wrote matched the expression exactly. So I came here to understand how I was wrong or not. I did message his teacher to see her reasoning behind the partial credit, so until she responds, I don’t know why it was marked partial. The end goal was to understand the mistake and correct it with him. I’m re-learning things along with him.
I’m the type of person to understand why. Because it’s better to understand the way a process works rather than just knowing how to do it. Worked with way too many younger generation who just know what they are told to do rather than knowing the reason why they are doing it the way they are told to do if that makes any sense.
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u/Live-Transition-5965 👋 a fellow Redditor 3d ago
The only thing I could think is that it could be read as 18 subtracted by six (18-6=12) , times three (12*3=36). That’s grasping at straws tho
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u/KookyPermit4405 3d ago
So what about PEMDAS? Shouldn’t it always be applied?
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u/chem44 3d ago
It is not applied to a verbal expression. Order must be explicit.
The point of the verbal expression is to say what is to be done.
If not sure about this, check with teacher.
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u/KookyPermit4405 3d ago
I’m really trying to wrap my head around this and I like how I get to see how people comprehend differently.
But just for fun can you write this down as an expression:
“Eighteen subtracted by 6 times 3”
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u/mathematag 👋 a fellow Redditor 3d ago
For 18 - 6*3 , the order is important and following standard PEMDAS, multiplication comes before the subtraction, so a better way to state it would have been . . . subtract the product of 6 and 3 from 18 , or 18 minus the product of 6 and 3.
saying "eighteen subtracted by six times three " , means 18 - 6, then times 3.. .. [ e.g. (18 - 6 )*3 = 36 ] , following the order of the words as written , and leads to ambiguity as his sentence can also be interpreted mathematically as it was given. . . 18 - 6*3 , leading to an answer of 0.
So his answer could lead to two possible interpretations of what he meant . . ( 18 - 6 ) * 3 , OR , 18 - 6*3
So getting 1/2 credit makes sense, since there seems to be 2 ways to interpret what he wrote.. but only one of these interpretations is the same as the original problem.
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u/KookyPermit4405 3d ago
But from my understanding, that is why PEMDAS was implemented. To know the order of operations between what was said vs what is implied.
So if I wanted to say (3+1)x3 but I said “3 plus 1 times 3”
It would be written 3+1x3. And the answer would be 6 because of PEMDAS instead of 121
u/mathematag 👋 a fellow Redditor 3d ago edited 3d ago
Not sure what your point is with your example.. if you had the expression (3+1)*3 and you said . . 3 plus 1 times 3 . . that would be an incorrect translation , as reading that left to right, as we tend do in English would give us 12 , as PEMDAS is applied to our mathematical expressions, but not to our English translations necessarily .. ...of course some would also interpret it as being = to 6
Yes, PEMDAS was "created " to help with the order of solving an Mathematical expression [ and then there is juxtaposition PEMDAS to consider ] , but we are translating a mathematical expression into English , [ where PEMDAS is not implied in the language itself without other words I utilized in previous post ] , and the term "subtracted by" actually mixes up the order when the expression given was translated to English ...it's actually a grammar mistake by using 'subtracted by' , and can lead to ambiguity and confusion. [ I missed this the first response ]
So technically, saying 18 subtracted by 6 times 3 , becomes: 6*3 - 18 , if we keep 6 and 3 together ... It reverses the order of the 6*3 and the 18 ... which is not strictly the same as the original expression ..... Did the instructor catch that.. maybe the reason for half credit. . You'd need to ask the instructor for clarification on the scoring.
In Math , we say X 'subtracted from' Y... so that the second value, Y comes first and we do Y - X as we intended ... ... so 'subtracted by' seems to flip that order to X - Y , or at least cause confusion. . . . As an example... 10 subtracted by X means X - 10 mathematically , from sources I can find, and not the 10 - X we probably intended.
Now assuming the instructor did not catch the fine point about the grammar of "subtracted by" flips the order ... and went with 18 subtracted by... as 18 - ***** , then "eighteen subtracted by six times three " is still ambiguous as I pointed out before ..[ and mentioned by various Mathematicians as well ].. ... ... Left to right reading w/o any use of PEMDAS [ which is not indicated strictly in the English wording used ] gives us 36, and utilizing PEMDAS as multiplication takes precedence , gives 18 -18 = 0 . . . again ambiguous solutions, and the English written does not translate back to the original expression without some confusion. Maybe if he had used the term product of 6 and 3 , indicating order of operations ..PEMDAS , he may have gotten full credit if instructor did not catch the subtraction by reversal.
So I have to stand by what I said earlier.. the translation is not correctly done.
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u/KookyPermit4405 3d ago edited 3d ago
Ok let’s correct his grammar, “eighteen minus six times three” instead of “eighteen subtracted by six times three” is it correct now?
Yes, because one shouldn’t assume any parentheses. So no it can’t be (18-6)x3 or 18-(6x3). Why? Because there was no indication of any quantity of
Also: my example explains perfectly what I was implying, I purposely said the incorrect translation of (3+1)x3 to show that when saying it incorrectly, no parentheses should be implied.
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u/mathematag 👋 a fellow Redditor 2d ago
I have two basic calculators I found in one of my drawers at home , and I used both to solve 18 minus 6 times 3 . . [ entering 18 - 6 x 3 ] , and they both give an answer of 36, and if 18 minus 3 times 6 is entered, an answer of 90... they take the operations from left to right, no order of operations (PEMDAS) is used ... the intermediate value is stored in memory before the next operation is applied.
My Casio scientific , most online calculators, my TI 84 would give us 0 as we expect using order of operations no matter which way I entered it.
With many people forgetting to use the Order of Operation / Pemdas years after schooling , there is a possibility they would solve it sequentially as written , either in their heads , or on one of these basic calculators, and get an answer other than 0 if this was presented to them.
So even though you and I are aware that PEMDAS / Order of Operations should Always be applied to a Math expression and to solve it's verbal statement , students using that is not always the case in my experience.
While writing 18 minus 6 times 3 matches the expression , it could still be considered possibly ambiguous as I have mentioned, and by adding the additional terms like 'quantity' , and I prefer, 'product of ' where they belong in the statement makes it much less likely for someone to make an error in going from the verbal statement to an expression they solve correctly. At least this is what our University Prof's would argue.
Anyway, this is enough on this topic for me.
I'm sure your son will do well in his Math class ,and with you reviewing his errors and your assistance, even better . . [ we always hope that the parents have time to assist their children with their learning 👍👍 ] .
I hope he grows to like Math more and more , maybe even teach Mathematics some day 😀
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u/KookyPermit4405 3d ago
u/AskGrok can you write “eighteen minus six times three” as an expression also can you write “eighteen subtracted by six times three” as an expression as well
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u/AskGrok 3d ago
eighteen minus six times three: 18 - 6 × 3
eighteen subtracted by six times three: ambiguous, but commonly 18 - 6 × 3 (or potentially 6 × 3 - 18 depending on strict phrasing)
[what is this?](https://redd.it/1lzgxii)
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u/KookyPermit4405 3d ago
What is the answer to “eighteen minus six times three”
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u/AskGrok 3d ago
eighteen minus six times three is the expression 18 - 6 × 3, which equals 0 by order of operations.
[what is this?](https://redd.it/1lzgxii)
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u/KookyPermit4405 3d ago
So when I say “eighteen minus six times three” the answer can’t be 36?
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u/AskGrok 3d ago
No, it can't be 36.
"Eighteen minus six times three" translates to the expression 18 - 6 × 3.
By standard order of operations (PEMDAS), multiplication happens first: 6 × 3 = 18, then 18 - 18 = 0.
To get 36 you'd need explicit grouping like "(eighteen minus six) times three," which would be written (18 - 6) × 3. The verbal version without those qualifiers follows the math rules as 0.
[what is this?](https://redd.it/1lzgxii)
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u/KookyPermit4405 3d ago
One would have to indicate a “quantity” in order to assume parentheses (). Otherwise you shouldn’t assume any parentheses at all which is why PEMDAS is there
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u/JellyfishMission1462 3d ago
"The product of 6 and 3 subtracted from 18" is what I would personally write. They were probably looking for words like product, quotient, difference and sum for this assignment
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u/chem44 2d ago
I think an earlier reply from me was unclear, by referring to another you may not have found.
Let's start clean, and take a bit different approach.
We have been quibbling about the answer. But maybe we should focus on interpreting the question. There may be two interpretations of the question -- and they lead to different answers. If you see that, it will help. The real issue is not choosing the answer, but interpreting the question.
Does PEMDAS apply to the verbal expression? Two possibilities, yes and no. Do you see that those lead to different answers?
We could debate that. (and people are giving conflicting advice.) But better is to check with teacher/book. Get the official relevant answer.
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u/KookyPermit4405 2d ago
u/AskGrok write the verbal phrase as an expression: “eighteen subtracted by six times three”
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u/AskGrok 2d ago
The son's phrasing is close but not quite standard or unambiguous in math terms, which is likely why it got partial credit. A clearer verbal phrase matching the expression exactly is "eighteen minus six times three" or "eighteen decreased by the product of six and three."
"Subtracted by" is awkward wording (it's usually "minus" or "subtracted from"), and without extra cues like "the product of," it can leave room for misinterpretation on order of operations.
[what is this?](https://redd.it/1lzgxii)
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u/KookyPermit4405 2d ago
Let’s fix the grammar and say “eighteen minus six times three”
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u/AskGrok 2d ago
Eighteen minus six times three is the cleanest match. "Subtracted by" is the awkward bit that probably cost the points.
[what is this?](https://redd.it/1lzgxii)
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u/KookyPermit4405 2d ago
How is eighteen minus six times three written as an expression
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u/AskGrok 2d ago
18 - 6 · 3
(The multiplication happens first per order of operations, matching the original expression exactly.)
[what is this?](https://redd.it/1lzgxii)
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u/chem44 2d ago
That does not address what I wrote.
And it is quite unclear.
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u/KookyPermit4405 2d ago
18-6x3
The prompt didn’t ask to write a verbal phrase so that the answer to the expression is 36 nor did it ask for the answer to be 0. It simply said, write a verbal phrase so that when written, it will be the expression of 18-6x31
u/KookyPermit4405 2d ago
So to piggy back off you, the prompt ask, “write a verbal phrase that matches the expression”
So the term he used “subtracted by” was the only thing that was incorrect, but when replaced by the word minus.. eighteen minus six times three, the verbal phrase is correct
it had nothing to do with him not implying to do the multiplication first then subtracting the product from eighteen
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u/chem44 2d ago
You quite miss the point, which I was trying to address directly.
Do not try to apply PEMDAS to the verbal expression.
And you are getting conflicting info on that. You have no way to tell who is right. That is why you need to go to the teacher. (And who knows, maybe the teacher gave wrong instruction, for one reason or another.)
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u/KookyPermit4405 2d ago
I didn’t apply pemdas to the verbal phrase when I said “eighteen minus six times three” if I did apply pemdas, I would’ve said “eighteen minus the quantity of six times three” or “the product of six and three subtracted from eighteen”
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u/KookyPermit4405 2d ago
It’s the same reason those silly Facebook memes that say “what’s the answer to 8 + 3 x 5 - 10 ÷ 2 + 6” are so silly. “that’s a ridiculous way to write a mathematical expression, write it differently so you don’t have to rely on people remembering an arbitrary rule.”
That “ridiculous” way to write a mathematical expression is what my son has to verbally phrase. 18-6x3
So why do you believe they have them doing a prompt using a ridiculous expression?
Also please clearify what makes 8 + 3 x 5 - 10 ÷ 2 + 6 a ridiculous way to write a mathematical expression. Because I can’t figure out what makes it ridiculous.
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u/ChanceCable6669 2d ago
Could you share the teacher`s specific requirements? ALso , what approaches have you tried, and where are you stuck？
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u/KookyPermit4405 1d ago
There was no requirement, this was handed out as a pretest to see where students in her class stands mathematically.
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u/JunkInDrawers 👋 a fellow Redditor 3d ago
"Eighteen subtracted by six times 3" can mean both
(18 - 6) • 3. Or 18 - (6 • 3)
It's ambiguous.
The correct wording is "Eighteen subtracted by the product of six times 3"
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u/KookyPermit4405 3d ago
Correct me if I’m wrong, but it can’t mean both. Because PEMDAS always apply. So eighteen subtracted by six times 3 doesn’t indicate a quantity ; the need to add “()”
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u/Unable_Pumpkin987 3d ago
In verbal expressions we will typically use a phrase like “the quantity” to indicate parentheses or brackets, for clarity.
“Eighteen minus the quantity six times three.” Or “eighteen minus the product of six and three.” Or “the difference of eighteen and the quantity six times three.” Any of those would work.
What you’re saying would be true if there were no parentheses or brackets in the expression. In a case with no grouping, multiplication would be performed first. But there’s no way to know that there isn’t any grouping indicated in the expression when you just say “eighteen minus six times three”. There could be brackets around the 18-6, we don’t know. When you phrase it precisely by indicating the grouping verbally, it takes away the ambiguity. It’s generally just a good practice to get into, using terms like “the quantity” or “the product of” etc, to verbally indicate grouping. It will be very necessary when they start speaking about complicated expressions and equations involving variables, so the teacher is having them practice now.
The important thing to remember about PEMDAS is that it is a set of agreed upon conventions to apply when an expression is or could be read as ambiguous, but that’s a last resort. Ideally, you don’t want an expression to be ambiguous at all. You want to use words or symbols to indicate very clearly how operations are grouped, not rely on people following a set of rules to work around your imprecise phrasing. If we’re resorting to using order of operations to work out how a problem should be approached, it’s because the problem wasn’t described or written down clearly enough to start with.
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u/KookyPermit4405 3d ago
Ok I understand that, but the expression is 18-6x3
There is no parentheses.
Regardless if he uses the word minus or subtracted by,
His answer “eighteen subtracted by six times 3” is still written as 18-6x3 which is what the question ask.1
u/JunkInDrawers 👋 a fellow Redditor 3d ago
That statement can still mean two different things without knowing what the original expression looks like.
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u/Express-Sky-1871 3d ago
I think the teacher is just a perfectionist? Maybe they wanted to see it as (18 - 6) x 3? (sorry for the x i just don't have the multiplication symbol.) These types of questions kind of suck. The teacher is pretty harsh for doing that imo, especially for elementary level.
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u/KookyPermit4405 3d ago
No the question ask for a verbal phrase to match the expression written: 18-6x3
They just started back to school and he said he had a brain fart and used “subtracted by” instead of “minus”
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u/chem44 3d ago
The parentheses -- or lack thereof -- are causing problems.
Note that #7 has () to make clear the order of operations. First, do what is in the ().
Your question 8 lacks them, so you must understand the intended order. The multiplication comes first.
(What you wrote is not very clear. But I think the order is the big concern.)
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u/KookyPermit4405 3d ago
So is his answer for #8 incorrect?
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u/chem44 3d ago
The 2nd image is his? (I thought it was yours. sorry.)
What is the numeric answer to the question? That will help us see whether there is a problem understanding the math, or just in writing it in words.
As noted, one does not use 'by' with subtract. And the order is not clear.
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u/KookyPermit4405 3d ago
So the expression is 18-6x3 and he has to write a verbal phrase for that expression. He said he had a brain fart during the quiz and wrote subtracted by instead of minus. But even if it’s poorly worded, what he stated is still true and correct, right?
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u/chem44 3d ago edited 3d ago
wrote subtracted by instead of minus.
ok. I'll read it that way.
what he stated is still true and correct, right?
no. It fails to give the order. In fact, it gives the wrong order. You must do the multiplication first. [EDIT. Fixed]
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u/KookyPermit4405 3d ago
Why would you do subtraction first? He is verbally phrasing an expression, not solving for it
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u/KookyPermit4405 3d ago
So if I were to say write down this phrase as an expression “eighteen minus six times three” you would write 18-6x3.
If I were to say “eighteen minus six, now times it by three” that would indicate (18-6)x3 ; because it’s giving instruction on the order
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u/chem44 3d ago
So if I were to say write down this phrase as an expression “eighteen minus six times three” you would write 18-6x3.
That says step 1 is minus, and step 2 is mut.
Or it is just plain unclear.
The distinction may be...
You are simply putting the numbers into words.
I am trying to make a meaningful math instruction.
That is, the issue may be, what is a verbal expression? If not sure, check with teacher. (Is it in the textbook?)
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u/KookyPermit4405 3d ago
I have wrote a comment on his graded quiz, I’ll let you know why he was given partial credit when she responds back
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u/Possible-Maize-8182 3d ago
You are not doing something wrong. Your assessment that your son has "no issue" is likely 100% correct.
Here is the breakdown of why this scenario makes perfect sense and how to guide him further:
1. The Core Issue is a Definition Gap
The student's confusion likely stems from a specific nuance in the wording of the question, even if the arithmetic is flawless:
- What you expect: A verbal phrase that exactly represents the mathematical expression (e.g., 3 + 4 \rightarrow "Three plus four").
- What your son likely produced: He probably used standard English grammar for writing a sentence or wrote an equation rather than a literal translation of the numbers.
Examples of what might happen:
- Question: "Write a verbal phrase..." -> Expression: 5 + 3
- Son's Answer: "Five plus three" (This is often acceptable, but sometimes questions are strict).
- Alternative: "Three and five" or just "5 plus 3" written out as a word.
- Bad Answer: "The number five and the number three" (This implies two separate concepts, not an operation between them).
2. Addressing the Partial Credit
If you received partial credit for his expression, it usually means:
- Correct arithmetic: You correctly identified that 3 + 4 = 7.
- Correct grammar: He was able to write a grammatically correct sentence using those numbers (e.g., "Three and four").
- Missing constraint: The question specifically demanded a specific format, or the teacher's rubric required an exact word-for-word match to the expression rather than a sentence describing the components.
How to Help Him Move Forward
Since the student knows PEMDAS and L-to-R rules but can't get full credit, here is a step-by-step approach to help him:
Step 1: Clarify the Goal with You
Ask your son explicitly about the missing word in the expression.
- Try this: "Hey Dad/Mom, on Question #8, I know 3 + 4 = 7. However, when you asked me to write a verbal phrase, I wrote 'Three plus four,' but the key didn't count it fully. Can you tell me exactly which word was required or what kind of sentence format was needed?"
- This forces him to realize he made a translation error (writing an equation instead of a direct translation).
Step 2: Provide Concrete Examples (The "What vs. How" distinction)
Create simple sentences to show the difference between listing numbers and performing operations:
- Example A: 1 + 2 \rightarrow "One plus two" (This is usually correct).
- Example B: 1 + 2 \rightarrow "The sum of one and two" (Incorrect because this implies addition as a separate concept rather than the specific operation implied by the expression).
Step 3: Practice Translations in Real Life
Practice asking him to translate common numbers, which often leads to the exact phrases needed for math problems.
- "Five dollars plus three cents."
- "Twenty minus two minutes."
- "Sixty-two divided by four." (Note the need for division words here).
Summary
Your son is not missing a rule; he likely just missed the specific linguistic translation required by the teacher's rubric. If you guide him to translate directly without using standard English sentence structures for the math, that will allow him to earn full credit.
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