So, you have made it to the third of our Difficult level Eleven Plus maths quizzes on Percentages – give yourselves a pat on the back! As you will know by now, percentages are a way to represent proportions of numbers, but how do you calculate them? In the last quiz we showed you one method. Here’s another which you might prefer:
What percentage of 70 is 28?
First divide 70 by 100 to work out what 1% of 70 is:
70 ÷ 100 = 0.7
Next, divide 28 by 0.7 to work out how many “lots” of 1% are in 28:
28 ÷ 0.7 = 40
So, there is your answer: 28 is 40% of 70
This method is great for estimating your answers, but it often requires a calculator!
So now, on with the quiz. You can use the method above, or the one we showed you in our previous quiz. Alternatively, you may have your own method. Use whichever you prefer – as long as it gives you the right answer!
To find 20% of 40, divide by 100 then times by 20:
40 ÷ 100 = 0.4
0.4 x 20 = 8
A quicker way to find 20% is to simply divide by 5 (because 20% is the same as one-fifth)
40 ÷ 5 = 8