Should I correct the teachers markings?

[RapscallionKat]

DD came home with her homework marked.

With this...

"Silly mistake"

It's right 🤔

She would have got full marks but got 29/30 because of this.

I guess it's the comment that's annoyed me. The fact she's been told she's being silly when it's correct.

I'm probably just being a nobby

Nothing wrong with OP's apostrophes.

There’s one missing in the title.

I have dyslexia and dyscalculia so I'm probably not the best person to judge.

I thought DD was right. So did DH. Guess I don't understand the workings out.

How could you both have thought she was right?

The question is

386 = X - 473

So X must be greater than 483

X = 386 + 483

X = 859

I have dyscalculia and DH had come back from a 12 hour night shift. Meh.

Did you tell your DD the teacher was wrong and she was right?

With the greatest respect, maybe as maths is not your strong point, leave it to the teacher?

I think it’s because the way the calculation is written is designed to test you understand what is being asked. If you turn it round and write X - 473 = 386 it’s easier to see that X needs to be quite a big number.

Checking teachers' marking is perfectly legit. A lecturer once incorrectly tallied a grade for me so badly that it could potentially have affected my degree classification. I was pleased I noticed that.

However, the correct response is probably to politely query rather than to go in all guns blazing

Nothing wrong with checking marking. I'm a teacher and I know we're not infallible. But you probably want to check that the teacher is definitely wrong before raising it!

386 = 򪪪 - 473
is the same as
򪪪 - 473 = 386
you can work it out by adding 473 + 386 to get
859 - 473 = 386
which if you flip it back is
^386 = 859 - 473"

With the greatest respect, maybe as maths is not your strong point, leave it to the teacher?

This with bells on.

I think the comment about a silly mistake had annoyed you and it’s made you jump too quickly into defence mode.

I read that as the sum being laid out backwards

386 = ? - 473

reverse it is 473 - ? = 386

Otherwise the question should have been laid out as ? - 473 = 386

So it's a silly question as it's too ambiguous what is wanted.

Yeah sure OP correct it and send it back 😂 it'll give them something to laugh about in the staff room 🙄

it’s not ambiguous. There can only be one answer. X - 473 is not the same as 473 - X.

Weeping, addition and multiplication can be turned around but never subtraction or division. These have to stay in the exact order recorded.

how does that work with the answer being placed ahead of the sum? A sum's standard layout is number process number equals answer (X - Y = Z)

In my head if you move Z= to the beginning then the entire layout of the sum is flipped, not just part of it. It's a mirror image.

so 386 = ? - 473 is the mirror of 473 - ? = 386

Weeping, have you studied maths? It might be a standard layout and one that you are used to but it’s not the only layout and probably what this homework piece is trying to teach the children. You don’t ‘mirror image’ anything.

No it's not.

386 = ? - 473 is the mirror of ? - 473= 386

you have totally changed the order of operations if you switch the position of ? And 473

You could do it as a mirror image, yes

But that would be

-473 + ? = 386

Which would give the same number

Weeping you need to keep the '-' sign with the number so it's not 473, its -473.

@Acis There's an apostrophe missing in the title.

Weeping , it can help to imagine that the minus or plus sign is part of the number that makes it either positive or negative and cannot be separated from it. You can’t put it as a mirror image. The number is -473. The sum is +386 = +X -473. You can write this as +X -473 = +386. Or -473 +X = +386. If you put in smaller numbers it’s easier to see. 5 = X -4. X would be 9.

OP, I think what you are seeing is that the little working out she did in the corner was correct.
The problem is, that working out didn't give he the right answer, she was doing the wrong sum.

I do find it odd that the teacher changed the 7/9, but I expect she initially thought the scribbled out number was an 8, and then realised it wasn't so the whole thing was wrong.

weeping, think of it with much simpler numbers.

8=3+5
5= ? - 3 or ? -3 = 5

My brother's English teacher once wrote "His spelling is carless" on his report. My parents couldn't wait for parents' evening to point it out to her! Bit mean of them, I thought, as she was newly qualified.

Would you have been happier if the teacher hadn't written anything? I would take "silly mistake" to mean that she knows your daughter understands the process but just got a bit careless.
If the only reason you want to correct the teacher's comment is because she used the word "silly" you're going to spend a lot of time trying to find things to correct every time your daughter makes a mistake and has a comment pointing this out.
I don't know if the teacher put the 9 in but didn't correct otherwise was carelessness on their part or just to give your daughter a starting point to work out where she went wrong.