Count on Addition or Subtraction -- Am I wrong here?

[jitterbug24]

Am I crazy or is the question marked wrong on this page following the way this was taught at the top of the page? The teacher maintains that the only correct method for how many more is subtraction and that she didn't teach a keyword strategy different than the book. My son is working several grade levels ahead in math, and I believe he understands this concept. But I guess I could be wrong. The school insists that he needs more practice in basic math.

 

[lev888]

Am I crazy or is the question marked wrong on this page following the way this was taught at the top of the page? The teacher maintains that the only correct method for how many more is subtraction and that she didn't teach a keyword strategy different than the book. My son is working several grade levels ahead in math, and I believe he understands this concept. But I guess I could be wrong. The school insists that he needs more practice in basic math.

You are not crazy.

 

[Otis]

The teacher maintains that the only correct method for how many more is subtraction

Then the teacher has ignored the assignment's specific instruction that allows modeling with either addition or subtraction.

 

[lookagain]

Am I crazy or is the question marked wrong on this page following the way this was taught at the top of the page? The teacher maintains that the only correct method for how many more is subtraction and that she didn't teach a keyword strategy different than the book. My son is working several grade levels ahead in math, and I believe he understands this concept. But I guess I could be wrong. The school insists that he needs more practice in basic math.

jitterbug, could you have the teacher and/or some other education official
from the school look at this forum page with the responses, particularly
at Otis's post #3? Your son, or whichever student wrote that response,
needs to get the full credit.

 

[Dr.Peterson]

Then the teacher has ignored the assignment's specific instruction that allows modeling with either addition or subtraction.

Not only does the page allow both methods, it explicitly demonstrates (and has the student trace over) an addition equation, and the whole point appears to be that the missing-addend concept and the subtraction concept are equivalent. The student has done exactly what the page calls for.

I would call this teacher malpractice.

 

[jitterbug24]

Thanks everybody. When I discussed this with the teacher previously, she didn't have any interest in considering a different answer. She believes any other answer than subtraction means he is less prepared for harder second grade math, as this was a first grade review lesson. Not sure if she believes she taught him something more advanced? I don't think this is the case? At very least, she could have acknowledged that giving him a page with an example other than what she considers correct is misleading, but she seemed unaware or didn't care.

It's just a question on a homework assignment, so it's not really a big deal in the grand scheme of things. But her response was very off-putting, and I have some concerns about how the material is being taught and her attitude toward my son. His grades now are just on grade level. For exemplary, she has stated that a 100% or close to it is needed on second grade testing, not sure if that includes homework. Above grade level knowledge or aptitude isn't a factor, so the grading becomes meaningless and irrelevant unfortunately.

 

[lev888]

Thanks everybody. When I discussed this with the teacher previously, she didn't have any interest in considering a different answer. She believes any other answer than subtraction means he is less prepared for harder second grade math, as this was a first grade review lesson. Not sure if she believes she taught him something more advanced? I don't think this is the case? At very least, she could have acknowledged that giving him a page with an example other than what she considers correct is misleading, but she seemed unaware or didn't care.

It's just a question on a homework assignment, so it's not really a big deal in the grand scheme of things. But her response was very off-putting, and I have some concerns about how the material is being taught and her attitude toward my son. His grades now are just on grade level. For exemplary, she has stated that a 100% or close to it is needed on second grade testing, not sure if that includes homework. Above grade level knowledge or aptitude isn't a factor, so the grading becomes meaningless and irrelevant unfortunately.

Yes, one assignment is not important in the grand scheme of things. What's important is her attitude. This is a huge red flag. This person is not a math teacher. She's a bureaucrat. She will instill a hatred for math in her students. And, as a bonus, a sense of fear of being treated unjustly by a teacher.

 

[topsquark]

Thanks everybody. When I discussed this with the teacher previously, she didn't have any interest in considering a different answer. She believes any other answer than subtraction means he is less prepared for harder second grade math, as this was a first grade review lesson. Not sure if she believes she taught him something more advanced? I don't think this is the case? At very least, she could have acknowledged that giving him a page with an example other than what she considers correct is misleading, but she seemed unaware or didn't care.

It's just a question on a homework assignment, so it's not really a big deal in the grand scheme of things. But her response was very off-putting, and I have some concerns about how the material is being taught and her attitude toward my son. His grades now are just on grade level. For exemplary, she has stated that a 100% or close to it is needed on second grade testing, not sure if that includes homework. Above grade level knowledge or aptitude isn't a factor, so the grading becomes meaningless and irrelevant unfortunately.

In addition to lev888's comment "modern" Mathematical teaching practices are, IMHO, crude and in some cases just wrong. For example, in 3rd grade math it is apparently now common to claim that 3 times 2 is not the same as 2 times 3. (3 groups of 2 vs. 2 groups of 3.) The reasoning is that this becomes an important fact later on in their education. Yes. Later on as in "late High School" or "early college." This teacher is setting the same kind of example: the addition and subtraction methods are essentially the same thing and to say one is right and the other is wrong is simply absurd.

-Dan

 

[Otis]

Not only does the page allow both methods, it explicitly demonstrates ... an addition equation, and the whole point appears to be that the missing-addend concept and the subtraction concept are equivalent.

A very useful lesson. I often use addition when subtracting numbers mentally. For example, I don't borrow from adjacent place values in my head with something like 534-417. Instead, I count up from 417. Easier. Faster.

417
add 3 makes 420
add 80 makes 500
add 34 makes 534
34+3+80 = 534-417

Thank goodness I can still add 37+80 mentally.

?

 

[Otis]

in 3rd grade math it is apparently now common to claim that 3 times 2 is not the same as 2 times 3.

Yet, they likely still hand out printed multiplication tables that show 2x3 is the same as 3x2. I'd like to see a lot more lessons in grade school demonstrating how often that "different" parts of math are closely related by patterns and perspectives.

The reasoning is that this becomes an important fact later on

Oh, brother! Have they stopped using x as a multiplication sign starting in second grade, too?

Sounds more like inconsistent, personal agendas than anything research-based.

 

[topsquark]

Sounds more like inconsistent, personal agendas than anything research-based.

Welcome to methods that "professional" (PhD) educators come up with when they've never actually taught the material themselves.

-Dan

 

[lev888]

The reasoning is that this becomes an important fact later on in their education.

Ok, I give up. What is this important fact?

 

[topsquark]

Ok, I give up. What is this important fact?

That not all binary operations in Mathematics are commutative. The cross product for vectors, for example. But this is so far above 3rd grade that I find it to be ridiculous to "prepare for it" at the 3rd grade level. I wouldn't mention it until the student runs into non-real number systems.

-Dan

 

[lev888]

That not all binary operations in Mathematics are commutative. The cross product for vectors, for example. But this is so far above 3rd grade that I find it to be ridiculous to "prepare for it" at the 3rd grade level. I wouldn't mention it until the student runs into non-real number systems.

-Dan

Yes, not all operations are commutative, but this one is. If we continue this line of so called reasoning, it would mean that to find the area of a rectangle we need to multiply length by width and not the other way around. So why are geometry students so callously left unprepared for vector cross product?

 

[Otis]

What is this important fact?

You meant that as a rhetorical -- correct?

 

[lev888]

You meant that as a rhetorical -- correct?

No.

 

[Otis]

Thanks. I wasn't sure whether you and Dan were discussing opposing viewpoints.

 

[Steven G]

8 + 5 = 13 and 13-8 =5 are the same statement. A fact that is in my opinion EXTREMELY important for an Algebra student to know. For example to solve 8 + x =13, just compute 13 - 8 to get x. I don't think that subtracting 8 from both sides is the best way (not a bad way just not the best way) to solve this type of equation.

The problem clearly stated that one can use addition or subtraction--after all, they are basically the same.
Now, if the teacher insisted that these type problems should be solved by subtraction then I can see why she marked the problem wrong. If this is true, then she is a terrible teacher since she does not allow her students to think! A teacher that doesn't allow their students to think is by far the worst type of teacher.

On a positive note about teachers, in my daughters public elementary school all her teachers promoted thinking. To be honest, I was shocked. Now that my daughter is in high school, that has changed. The teachers do not have enough confident in math to allow students to think differently. Many of the math teachers only know one way to do a problem and will never deviate from that. This is quite sad.

 

[lev888]

Kid’s seemingly correct answer on a math test has the Internet up in arms

A simple answer raises plenty of questions.

www.upworthy.com

 

[jitterbug24]

Is the discussion about multiplication possibly why the teacher is nitpicking about showing work on this question?

What's funny is they seem to think my son memorizes everything. But if you ask him a similar multiplication problem, this is one of the strategies he uses. He's never done flashcards, but his mental math, even with multiplying double digit numbers beyond 12X12, is very strong. He has learned from books by Greg Tang and Danica McKellar, which I thought were in keeping with what would be taught in school.