Percentages
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oh sorry!!! read it too quickly, and wondered, rather why someone had needed to ask how to do it 
hush ma mouth, etc.
Sorry, all. In a frenzied catch up following hours on the motorway (crashes each way involving LONG tail backs) and a vomiting child during one of the lengthy sessions. And no wipes. Nice. Escaped to the relative sanity of the site on my return and was clearly still a little light headed!
hush ma mouth, etc.Sorry, all. In a frenzied catch up following hours on the motorway (crashes each way involving LONG tail backs) and a vomiting child during one of the lengthy sessions. And no wipes. Nice. Escaped to the relative sanity of the site on my return and was clearly still a little light headed!
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hermanmunster
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Re: Percentages
Taught my DD how to work these out arithmetically if necessaryHaze wrote:We have come across a few of these questions: Eg. a grid of 32 squares has 20 shaded. What is the percentage of shaded squares?
The answers are all very close, so guestimating isn't an option. Is the only way to do the long division of 20/32?
That would take me a few minutes to complete with a pencil, never mind my DS in an exam!
20/32 x 100/1
But told her always to first try to simplify the fraction down to one she could either convert easily to a decimal, or to a percentage, e.g I/10's, 1/25's, 1/5's, 1/4's, 1/8's.
This example simplifies down to 5/8, and this is a fraction for which the decimal equivalent of 0.625 should be learnt (along with the rest of the 1/8's, 1/4's, and 1/5's).
Then from 0.625 it should be known that this equates to 62.5%
No, he needs to know how to simplify fractions. It helps in all sorts of questions.Haze wrote:Just been through it with DS.
He has never simplified fractions and, while it's easy, he would have to remember that, plus remembering all the percentages of fractions, then do a multiplication at the end.
I'm wondering if the long division is easier, with less margin for error
I printed off a number of worksheets for DD to practice.
Try googling maths factory worksheet, or similar, and see what comes up.
Have a look at...
http://www.bbc.co.uk/schools/ks2bitesiz ... ead1.shtml
From the way you are describing DS then perhaps the easiest way, is to work out what each of the 32 squares equals.
Each square =100 divide by 32 = 3.125
20 squares are shaded so 20 X 3.125 = 62.5%
http://www.bbc.co.uk/schools/ks2bitesiz ... ead1.shtml
From the way you are describing DS then perhaps the easiest way, is to work out what each of the 32 squares equals.
Each square =100 divide by 32 = 3.125
20 squares are shaded so 20 X 3.125 = 62.5%
Thanks for that Mitasol. I think you are probably right.
Rightly or wrongly, I am trying to teach him how to solve problems rather than what the answers are to common problems.
He still can't remember the times tables so I don't expect him to remember what 1/12 is as a decimal. But he will know how to work it out and when it is appropriate to carry out that calculation.
I realise it's slower but, for my DS, I think it's far more accurate.
Rightly or wrongly, I am trying to teach him how to solve problems rather than what the answers are to common problems.
He still can't remember the times tables
so I don't expect him to remember what 1/12 is as a decimal. But he will know how to work it out and when it is appropriate to carry out that calculation.I realise it's slower but, for my DS, I think it's far more accurate.