Primary Resources have an excellent powerpoint resource - Percentages, Fractions of 100,
that is worth working through with your child. As is this Percentage Squares worksheet.
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To find the percentage of a number we divide the total amount by 100 - this will tell us what 1% of the total is, and then multiply by the amount that we wish to know.
To find 10% of 100, divide 100 by 100 = 1, then 10 x 1 = 10 ... 10% of 100 is 10
To find 10% of 50, divide 50 by 100 = 0.5, then 10 x 0.5 = 5 ... 10% of 50 is 5
(remember that to divide by 100, shift the number 2 places to the right)
To find 15% of 300, divide 300 by 100 = 3, then 15 x 3 = 45 ... 15% of 300 is 45
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Another method of finding the percentage of a number is to change the percentage required into a decimal and the multiply the number by it.
30% means 30 out of 10, which is a fraction 30/100 - to convert fractions to decimals, we divide the numerator by the denominator - 30 ÷ 100 = 0.3.
So 30% is the same as 30/100 which is the same as 0.3
To find the percentage of a number we can multiply by the equivalent decimal.
To find 10% of 100, decimal equivalent of 10% is 10 ÷ 100 = 0.1, 100 x 0.1 = 10
(remember that to multiply by 100, shift the number 2 places to the left)
To find 10% of 50, decimal equivalent of 10% is 10 ÷ 100 = 0.1, 50 x 0.1 = 5
To find 15% of 300, decimal equivalent of 15% is 15 ÷ 100 = 0.15, 300 x 0.15 = 45
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Some percentages are worth remembering
50% means a half
25 % means a quarter
75 % means three quarters
10 % means one tenth
