We can use the same thought process as we did with percentages to find 1/16 th of the total enquiries and then scale it up to the number of 16 ths needed for each part.Īs 12,000 is the total and we want to calculate 1/16 th of it, we change the word ‘of’ to ‘divide’ and the calculation becomes:Īs 750 represents 1/16th of the total, we can ‘multiply’ it by 10 to calculate the proportion generated by newspaper advertising:Īgain we can check our answer, in this case by calculating the other two ‘parts’ and ensuring that when all three ‘parts’ are added together the answer is the total. If we had 12,000 enquiries in total, how many were generated by each source? So in this case 16 represents the ‘whole’.įinally, we can apply this knowledge and understanding to answer a question such as: We do that by adding all the numbers in the ratio: Next we need to understand the relationship of each part or proportion to the ‘whole’ and for that we need to calculate what the whole is. For example, newspaper advertising is 10 as a proportion of the whole, the website is 5 and referrals only make up the small proportion of 1. The word ‘respectively’ means that the order of the numbers in the ratio (10, 5 and 1) relate to the ‘parts’ in the same order. Or they can be described specifically using ratios, for example, the proportion of enquiries between newspaper advertising, the website and referrals is 10:5:1 respectively. Proportions can be described in general terms a small proportion of enquiries are generated by referrals. Firstly we need to know that when we talk about proportions, we simply mean a ‘part’, ‘share’, ‘bit’ or ‘number’ of a whole. Let’s now look at how this relates to proportions and ratios. Multiply by 100 to change a decimal to a percentageĮg.Divide by 100 to change a percentage to a decimal.It’s worth noting that we can convert between percentages and decimals: We can check our calculations by re-working it the opposite way, using the first technique, as now we could reasonably expect 5% of £600 to be £30.
However, this is where a connection comes in, as we’ve calculated a decimal, and now need to ‘multiply’ that by 100 to convert it back into a percentage: When we substitute ‘divide’ for ‘of’ the calculation becomes: We can turn the maths into English here too, as we want to know what 30 is as a percentage of 600. We might also need to calculate an amount as a percentage of another, for example £30 as a percentage of £600. So 8% of £26,500 is £2,120 Calculating an amount as a percentage of another The easiest way is to calculate 1% first and then scale that up to 8%.Īs £26,500 represents 100% and we want to calculate 1% of it, we change the word ‘of’ to ‘divide’ and the calculation becomes:Īs £265 represents 1% of the whole 100%, we can ‘multiply’ it by 8 to calculate 8%: We might need to calculate a percentage of a number, say for example 8% of £26,500. Percentages, proportions, ratios and fractions are subtly different, but related enough for the same techniques to be applied and manipulated, as long as we understand the connections.įirst we have to know that ‘per cent’ means ‘out of 100’ and that percentages are a way of working out part of a number ie. In effect, she translated maths into English for me and I’ve never looked back. Then a fantastic tutor told me about the word ‘of’ and how it can be substituted for ‘divide’.
Percentages were my pet hate and I was still phoning my Dad, years after I’d left home, to check whether I needed to multiply or divide by 100. Let’s just say I wasn’t the best at maths. When I told my family and friends that I was going back to college to study accountancy, they all thought it was a joke.
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