Another Sum I Don't understand !

[scarlett]

I'm trying to get ready for a day out and DS2 is booing his eyes out because he can't work out one of his homework sums ....I don't want to give him the answer , but can't help as I don't know how to do it either !

Apologies if it's a really easy one...I am dim , you know

1/2 - 9/11 .

He's changed the denominator into 22 for both , but then how do you take 18 from 11 ????

Thanks.

[hermanmunster]

....end up with a negative answer


1/2 - 9/11 = 11/22-18/22

answer = -7/22

[Waiting_For_Godot]

Poor Scarlett, not a morning person?

Herm's answer, unless he wrote the sums round the wrong way!

[scarlett]

DS1 did say it would be Herman's answer....but DS2 said he hadn't covered anything like that in class and I did think it seemed a bit tricky for year 5 Thanks anyway .

P.S I shall be taking special note as to your weak spots over the coming months, WFG...

[Guest55]

Yes - they don't normally look at fractions with different denominators and a negative answer is a bit weird!

[scarlett]

Yes, my DS1 has just looked at the replies and said ," But that's secondary school work ! "

Wondering now if I should tell DS2 to leave it or tell him it's a negative answer ( and leave him to work it out )

[hermanmunster]

is it on a printed sheet or did he write it down?

[scarlett]

It's on a printed sheet...some of his previous homework questions I often thought weren't quite right such as the one which states...

In a box there are 12 pieces of paper , each with a number. The first numbered 2, the second 4, the third 6 and so on until 12 ???? Surely that should read 24 ? It then goes on to say that if the box is shaken and the numbers are drawn out in pairs and the sum of each pair are.... 8, 12 , 24 , 28 , 40 and 44 what are the numbers that make up the pairs. However , we were told the numbers only went up to 12 so DS couldn't really do it ( but could with the numbers up to 24...but kept telling me it was just up to 12 as that's what the teacher had written.)

[aargh]

Just to be pedantic if it is a take away it is not a sum but a calculation