Can anyone help me know if the mark for dc maths HW is reasonable (year 8)

[Woollysheepo]

Pic attached. They were awarded 1 out of 6. TIA

I can't see pic

Oh now i can

A quick glance says it’s all wrong, so presumably marks for trying?

Just look at the first sum you see. 3x 6 =8?!?

Tell him to always look at his answer and make sure it makes sense - nearly 5 take away nearly 2 obviously can't equal one and a bit.

I think he got the mark because he had the idea to make both fractions into 24th's to balance them. So he got the first step right.

I see the method they think they’re trying to do (turn both fractions into 24ths) so I assume they’ve got the mark for that. But then it’s all gone wrong because they’ve written 2-1 rather than 4-1 and then it should be -2/24 rather than the +2/24 so it’s all a bit of a mess, I fear.

Not a teacher but they probably should:

1. Turn everything into 24th
2. Then they’ll have 114/24 - 44/24 = 70/24
3. 70/24 = 2 22/24
4. Which is 2 11/12

Ex maths teacher

it’s basically completely wrong.

he’s got the mark for the equivalent fractions. Lucky to get it.

What did you expect the mark to be?

My dc was surprised they got only mark I don’t know what it should be hence asking. They normally get better marks so thought I’d check.

Surely you can see that the sums are wrong, so a low mark shouldn’t be a surprise?

Presumably he meant to write '18' not '8' in the first step, as he then wrote that in the next line down. So that's probably what he got the mark for - turning them into equivalent fractions, with a suitable common denominator. (12 would have been better, but 24 is fine!).

The only way I can understand the 22/24 bit is that he's done the borrowing already, and the subtration, but not really understood that he did subtract!
So the 4 and 18/24 could turn into 3 and 42/24, and then when you subtract the 1 and 20/24, you do end up with the fraction part of 22/24 (but the whole number part is 3-1 = 2). So should be 2 and 22/24, simplifying to 2 and 11/12.

Perhaps he did the borrowing and subtracting part correctly to try to get 22/24, but then somehow also tried to subtract the 20/24 again, not realising that was what he was doing when he borrowed?! And he got confused about which whole numbers he was left with.

So 1/6 for the common denominator part seems very reasonable (tolerating his mistaken 8 for 18!).

Thank you for the advice it’s helpful.

I can see what he’s tried to do but only the first step is correct. The rest is all incorrect.

He’s correctly converted into 24ths which is what he got the mark for.

The step where he should have borrowed from the 4 wholes he’s forgotten to convert the whole he borrowed from into 24ths. He’s borrowed 4 quarters because that’s what the original question was. It should have been 42/24 - 20/24.

And he’s only borrowed one of the 4 wholes from 4 3/4 so the 2-1 step should be 3-1. which means he should have added 2 to the result of 42/24-20/24.

The only way I can understand the 22/24 bit is that he's done the borrowing already, and the subtration, but not really understood that he did subtract!

Pretty sure he borrowed 4 quarters here and forgot the conversion to 24ths

Shoot… I got 2and 3/4ths

hmmm.. my maths is terrible. I can't understand the question, the only thing i understood is they are trying to do: 18/24 - 20/24, which i calculated as -2/24, a strange fraction, but the only answer i can find for that fraction.

Oh wait. No I didn’t I just somehow simplified 35/12ths into 2 and 9/12 instead 2 and 11/12ths … I think in need to go back to school 😪

although im curious as to why everyone is going to 24ths instead of 12ths??

Yes I agree with others. He got the mark for understanding he needed a common denominator for the fractions. But the 8/24 is wrong (tho he does later make it 18) and the 2-1 gives him the wrong large number; plus he ends up with 1/12 and it should be 11/12.

If he thought it was the right answer, encourage him as a pp says to look at the question and make a rough answer. 4.75 – 1.83 must equal a bit less than 3, not just more than 1.

I always find that useful when doing percentages – if it should be about 80% and I end up with 1.4% I know I've got something upside down.

ETA: He has very neat writing and writing of figures btw

Well it’s all pretty much wrong. He’s not really showing any understanding of how to calculate this correctly. This is year 6 stuff. Surprised it’s worth 6 marks! Would only be worth 1 on a year 6 Sats paper.

I think because that’s what the OP’s DS has done.