Maths help - percentages

[MedwayMumof1]

Can anybody offer any suggestions to help my dd with percentages. She is fine at being able to calculate say 18% of 450 but struggles with questions that require her to calculate what % is shaded out of a number of boxes. She knows that the sum might be 12 out of 30 are shaded but cannot equate that into a %. I have tried explaining but she switches off and won't listen and I then lose patience Are there any websites with this kind of topic explained with examples and exercises to reinforce?

Any help appreciated from a worried mum (especially as the dreaded day is fast approaching!)

[T.i.p.s.y]

I assume you have told her that to find the answer would be:

12/30 x 100

that is the simplest way I know. If she can lower the fraction it is often much easier, so it would become 2/5 which is obviously 40%.

[dadofkent]

I assume you have told her that to find the answer would be:

12/30 x 100

that is the simplest way I know. If she can lower the fraction it is often much easier, so it would become 2/5 which is obviously 40%.

Have taught DD a number of ways including the ways TIPSY suggests. I agree the best way, assuming the figures allow, is to simplify the fraction, not necessarily into it's lowest form, until the denominator is one that can easily be converted into percentages, e.g. 50,25,20,10,8,5,4,2.

[T.i.p.s.y]

You are right DadofKent - 4/10 would be much easier.

[SSM]

To me it sounds that she can't quite visualise the concept of percentages and link this to the way she works percentages out. ie when you ask her the question 'what is 18% of 450' she knows the sum that she has to do, but she doesn't actually visualise it and that is why she then gets confused when it comes to the 'what percentage of the coloured blocks'.

I don't know if that makes any sense. I just realised how tired I am and so am taking myself off to bed.