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DD's Y7 Maths Homework - Help Please

(5 Posts)
LadyGlencoraPalliser Sun 28-Sep-08 11:44:22

DD has come home with a maths worksheet on directed numbers to complete. Most of it is fairly straightforward eg -13 + -19 etc.
Then we get +15 - -19 which has stumped her and me both. We also can't figure out why some of the questions are partly in brackets eg she has been asked
-16 + (-5) which she assumes is -21
and also (-16) + (-5). Is the answer to this also -21 or does the extra set of brackets mean something different?
She says they didn't cover this in class.
Please can anyone help, maths isn't my strong point, or DH's either.

peanutbutterkid Sun 28-Sep-08 11:46:53

Extra set of brackets doesn't mean anything, it's just there for clarity. Probably to show her how the brackets can help clarify.

15 - -19 = 15 - (-19) = 15 + 19... the minuses cancel out.

colacubes Sun 28-Sep-08 11:50:31

Oh heck, no clue but will ask my ds when he gets in, he is in yr 8. a good tool is the bbc website they have all the cirriculm on there by stages, have look.

i cant do the link thing but theres the address.

OhWellNeverMind Sun 28-Sep-08 11:54:14

Peanut butter is correct though. The brackets are there to distinguish between a number which is negative and the operation of subtracting.

Negative numbers can be easiest to work on a number may seem babyish but helps avoid confusion.

LadyGlencoraPalliser Sun 28-Sep-08 11:57:26

Thanks guys. I will go and explain it to her now. She is keen to get all her homework right - long may it last!

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