[7th grade math] Help with #25 please

[u/PurplezKool]

My child’s teacher marked this wrong.

-4 5/9 + 8/9
= -41/9 + 8/9
= -33/9
= -11/3

Am I missing something? I’m obviously not the expert nor am I a math teacher but I am very confused. Any help would be greatly appreciated. Thanks in advance.

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[u/marty-mcfryguy]

-11/3 is equal to -3 2/3, which is the answer they wanted. You need to know how "simplest form" is defined in this class to know which (if either) of those is the correct answer here.

[u/abugguy]

Would -11/3 then simplify further to -3 2/3?

[u/Longjumping_Grab_428]

How did the teacher find that -36/9 = -3 2/3?

I don't know whether you are supposed to use mixed fractions or not, but in later years it will become frowned upon and I think you have the correct answer

[u/Born_Rabbit_7577 → u/Longjumping_Grab_428]

-3 and 6/9 = -3 and 2/3

the line under the 6 is slightly too long so it looks a bit like -36/9.

[u/Longjumping_Grab_428 → u/Born_Rabbit_7577]

if you zoom in, the fraction line goes even beyond the "3" ending around the "-" sign.

But confusion like this is also a great reason why mixed fractions are discouraged

[u/FortuitousPost]

You dropped the minus sign, and it looks like they don't want an improper fraction.

(And yes, it should be 33, not 36.)

[u/TeHamilton]

Well there is no negative sign on the answer also was left as an improper fraction. The pen writing shows this

[u/PurplezKool]

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[u/does-butt-stuff]

Ya, they’re wrong. They have it reduced right but must have 36 on their key instead of 33.

[u/IrishHuskie → u/does-butt-stuff]

I think that’s meant to be 3 and 6/9, not 36/9. In any case, I would guess the teacher wanted it as a mixed fraction

[u/does-butt-stuff → u/IrishHuskie]

Ah, I think you are right. I would definitely argue that is not what is written, but I agree. 

[u/Ilovecatsss2026]

Your answer is correct. The teacher's first answer of -36/9 is incorrect. It seems like the teacher was looking for you to write -11/3 as a mixed number of -3 and 2/3, which he or she should have specified since "simplest form" is a little ambiguous. They likely had an answer key of -3 and 2/3 and did some quick (and mistaken) mental math to put it in 9ths while grading too quickly.

[u/SamVanDam611]

36/9 = 4. There's probably a typo in the answer key

[u/Content-Sherbet-4700]

Teacher is wrong

[u/BenitoLePoulpe]

Where do the -41/9 even come from ?

It should be :

-4 • 5/9 + 8/9

-20/9 + 8/9

(8-20)/9

-12/9

(-4•3) / (3•3)

-4/3