Maths question help (One more sorry!)

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kal12003
Posts: 169
Joined: Thu Mar 06, 2014 2:50 pm

Maths question help (One more sorry!)

Post by kal12003 »

Can anyone please explain the following :

In a survey of 85 people, every fifth person has a pierced ear. How many people had a pierced ear?

0.5 X 85
85 X 1/5 - Correct answer
5 ➗ 85
85 - 4/5 - Daughter's answer
85 X 0.25

Thank you.
Ess30
Posts: 140
Joined: Tue Feb 18, 2014 3:15 pm

Re: Maths question help (One more sorry!)

Post by Ess30 »

It's the definition of a fifth.
Ess30
Posts: 140
Joined: Tue Feb 18, 2014 3:15 pm

Re: Maths question help (One more sorry!)

Post by Ess30 »

Tbf - DD also fluffed that question first time round. I made a very unsympathetic :shock: face - which is maybe where I'm failing as a parent.
leanmeamum
Posts: 736
Joined: Sat Dec 03, 2011 4:14 pm

Re: Maths question help (One more sorry!)

Post by leanmeamum »

1 in 5 is 1/5 so answer is 1/5 of 85
fatbananas
Posts: 1411
Joined: Mon Mar 08, 2010 2:03 pm

Re: Maths question help (One more sorry!)

Post by fatbananas »

Kal12003, My DS fell down on both these questions and actually still doesn't like the 'which is the smallest?' question. And he's seen it several times now ....
Seize the day ... before it seizes you.
kal12003
Posts: 169
Joined: Thu Mar 06, 2014 2:50 pm

Re: Maths question help (One more sorry!)

Post by kal12003 »

Thank you all for taking the time to respond.
In this answer then is the X effectivelly representing of to get 1/5 of 85?
DD was confused by the 85 X 1/5 answer.
I think we are both verging on burning out! Glad it will be over in another 10 days.
zeinab
Posts: 353
Joined: Sun Jul 25, 2010 11:25 pm

Re: Maths question help (One more sorry!)

Post by zeinab »

Did you get 17 as the answer ? Another way is divide 85 by 5. Best of luck for your child X
mystery
Posts: 8927
Joined: Tue Jul 21, 2009 10:56 pm

Re: Maths question help (One more sorry!)

Post by mystery »

Maybe it is the way the fractions are written that is confusing her. 1/5 is the same as a 1 directly over a 5 with a short line in-between them. Maybe it's the slash rather than a proper-looking fraction that is flooring her? Sorry I cannot type it out correctly on here either. Maybe if you write the explanation down below out by hand for her and show her the vertical version as well as the slanty version it will make more sense to her.

Yes. One fifth of 85 means divide 85 by 5. 1/5 x 85 means divide 85 by 5. 1/5 of 85 means divide 85 by 5.

Think of it like this. How do you find one fifth of 85? You divide it by 5.

What does 1/5 x 85 mean? It means you multiply 85 by 1 and divide it by 5 -- just the same thing.

Your school sounds like it teaches maths badly just like ours. Grrrrr. Or maybe your daugher just misread the answer - see the final sentence in my response below.

Four fifths of them don't have a pierced ear.

How do you find four-fifths? You divide by 5 to find one-fifth and multiply by 4 to find 4 of them.

How do you write this? 4/5 x 85 or 4/5 of 85 or 4 x 85/5 ----- it does not matter in which order you multiply and divide - remember BIDMAS?

Loads of questions like this in Schofield and Sims.

If you left your daughter to do this kind of question without the multiple choice answers how would she write down the working?

Your daughter's answer would be correct if it said 85 - 4/5 x 85. 85 - 4/5 is 84 1/5 - a mixed number. Maybe she just wasn't reading thoroughly?
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