As a nation we are appallingly bad at maths. Four out of five adults have a low level of numeracy, meaning that they wouldn’t achieve a grade C at GCSE, says the charity National Numeracy.1 In the latest international survey of maths skills by the OECD, Britain’s 15-year-olds were ranked 26th out of 65 countries.2
Maths teaching all too often fails to inspire us, and that can leave us at a significant disadvantage. Being numerate and understanding basic maths concepts (addition, subtraction, multiplication and division) helps up with problem-solving and is essential in many forms of life and work. High numeracy is connected to higher wages and even better health, claims National Numeracy.3 It is also fundamental to the understanding of how our everyday finances works.
Of course, computers and smartphones are able to do a lot of the hard work for us nowadays. However, you cannot rely on them all the time and being able to make simple calculations in your head will ensure you will never be caught out.
Worried that your maths skills are rusty? Take our quiz which is designed to highlight where you need to do more work.
Let us start with a bit of mental arithmetic, which is useful for checking things like your change in the supermarket or even cooking dinner.
1. You are cooking some spaghetti. The packet of pasta says you need 300 grams for four people. How many grams of pasta do you need for 10 people?
A . 675 grams
B . 750 grams
C. 900 grams
The questions become a little bit more complex now so if you want to use a calculator you can.
2. Before travelling to Spain you change £600 into euros when the exchange rate is £1 = €1.40. You spend €678 and change the remaining euros back into pounds when the rate is £1 = €1.35. How much do you get back in pounds?
A . £86
B . £120
C . £142
ANSWER B. First multiply £600 by 1.40 = €840. Take away €678 to leave €162. Then divide €162 by 1.35 to get the answer.
These are found on everything from food packaging to restaurant bills, but a lot of people go weak at the knees when confronted by them. The thing to remember is that percentages are a way of expressing a number as a fraction of 100 — “per cent” means per hundred. So 25 per cent is 25 parts of 100, 50 per cent is 50 parts of 100. One hundred per cent is 100 parts of 100, in other words, the whole amount.
3. You score 75 per cent in a maths test made up of 48 questions. How many questions did you get right?
A . 34
B . 36
C . 38
ANSWER: B. The easiest way to do this is to first convert the percentage into a decimal number. Simply divide by 100 and remove the per cent sign. If you divide 75 by 100 you get a decimal number of 0.75. Then multiply 48 by 0.75 to get to the right answer.
4. You are in a restaurant and the bill comes to £67. You want to leave a 10 per cent tip. How much do you leave in total?
A . £72.70
B . £73.70
C . £77.60
ANSWER: B. Again you can turn the percentage into a decimal, by dividing it by 100 and removing the per cent sign: 10 per cent becomes 0.1. You then multiply by the decimal to get the answer. Using the above example, 10 per cent becomes 0.1, and so 10 per cent of £67 is £67 x 0.1 = £6.70. Or you can turn the percentage into a fraction. So 10 per cent would become 1/10. 10 per cent of £67 is 1/10th of £67 which is £67 ÷ 10 = £6.70.
5. You are earning £25,000 a year when you get a letter telling you that your salary will go up by 2 per cent next month. How much will you be earning?
A . £25,200
B . £25,400
C . £25,500
ANSWER: C. A percentage increase of 2 per cent would be 102 per cent of £25,000. 102 per cent as a decimal is 1.02 so 1.02 x £25,000 = £25,500.
6. Your favourite clothes retailer is offering 10 per cent off everything in a sale. You have your eyes on a coat which before the sale cost £92. How much could you buy it for now?
A . £80.20
B . £82.00
C . £82.80
ANSWER: C. You use the same method as in the previous question but in reverse. A percentage decrease of 10 per cent would 90 per cent of £92. 90 per cent as a decimal is 0.9 so you multiply 0.9 by £92.
Compounding, essentially earning a return on a previous return, means that even relatively small amounts invested can build into much larger sums over time.
When you invest money you will hopefully earn a return in the first year. The next year you earn a return on your original capital and the return from the first year. In the third year you earn a return on your capital and the first two years of growth.
7. You invest £500 and earn 5 per cent per year compound interest. How much money would you have after two years?
A . £550.30
B . £550.50
C . £551.25
ANSWER: C. In year one you earn £500 x 0.05 (5 per cent turned into a decimal) = £25. So going into year two your investment is worth £525. You then earn £525 x 0.05 = £26.25. Add £26.25 to £525 and you get the answer.
Probability is about the chance of something happening. This is sometimes expressed in percentages: a 60 per cent chance of rain in the next hour. Or as a figure between 0 and 1: the probability of something which is certain to happen is 1, while the probability of something which definitely will not happen is 0.
8. What are the chances of rolling a six on a dice?
A . 0.17
B . 0.45
C . 0.60
ANSWER: A. There are six faces altogether which means that there are six possible outcomes. However, there is only one face with a six on it so there is only one way of throwing a six. Therefore, the chance of throwing a six is 1/6 or 0.166666666, which is rounded up to 0.17.
1 National Numeracy, 26 February 2016
2 OECD: PISA 2012 Results, 3 December 2013
3 National Numeracy, 26 February 2016
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Money Means is a news and information series written by independent financial and consumer journalists and experts. FSCS launched Money Means in 2016 to help give people clear and useful information about personal finance, to increase their understanding and confidence when dealing with money.