Converting percentages back to fractions

[fatbananas]

I had a total brain meltdown at the weekend. I am sleep deprived but can someone please help!

If you know that a percentage for a test is 60% and that the test is out of 15, say, how do you find out what the original score out of 15 was? Thank you I know I'm going to hit my head on the desk when someone gives the the answer!

[yoyo123]

0.6 x 15

[kenyancowgirl]

Isn't it 60 divided by 100 (0.6) and then times by 15?

Answer = 9

Quick check is that 60% is more than half and 9 is more than half of 15...

At least, I think that's how you do it!!!

[fatbananas]

There should be a hand slapping forehead emoticon

Thank you both!

[kenyancowgirl]

heehee

yoyo was quicker than me!!

[mystery]

I suppose it is important to explain it in a way that the child can understand though.

60% is 60/100 and you are wanting to turn it into ?/15

So, 60/100 = ?/15 --- equivalent fractions ---- would this work for your son?

and could he then say that this means that 60 x 15/100 = ?

And do some cancelling down to 6x15/10 = 6x 3/2 = 3x3 = 9?

Seems long-winded but it works for anything without having to make any leaps in the dark or remember anything other than meaning of fractions and percentages.

[fatbananas]

Yes, that's probably what he would do, Mystery. It was my own brain glue that I was struggling with! I haven't given him the paper yet - paper 17 Bond 10-11 book 1 - I try to look at the paper first so I can help him should he come unstuck. I'm feeling incredibly behind; I feel we should be finishing book 2 by now. Then ironing out weak points, ready to start on papers by Easter.

[mystery]

I don't think you should feel behind. That's a lot of ground you have covered in quite a short time. A close relative only did Bond 9-10 and got 140 in the Kent maths if that is any consolation.

I'm feeling very behind --- DD's maths has gone back to being very slow and careless again. Goodness knows how she manages to be one of the best at school - they must all be rubbish. They don't seem to do maths very often and when I ask what they've done it sounds like stuff they should have done years ago. All very odd.

I'm trying now to cut some corners as I don't think we are going to get time to do cover the syllabus, do Bond books and do the 8 GL familiarisation papers for maths as well as everything else in the other 3 subjects.

[Guest55]

Please don't say 'cancelling down' - we are simplifying or looking for common factors.

[Proud_Dad]

Please don't say 'cancelling down' - we are simplifying or looking for common factors.

Isn't that just another phrase that means the same thing?

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