Everyday Maths 2
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3 Negative numbers

Negative numbers come into play in two main areas of life: money and temperature. Watch the animations below for some examples.

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Activity 6: Negative and positive temperature

  1. The table below shows the temperatures of cities around the world on a given day.

Table 2

London Oslo New York Kraków Delhi
4˚C −12C 7˚C −3˚C 19˚C

    1. Which city was the warmest?

    2. Which city was the coldest?

    3. What is the difference in temperature between the warmest and coldest cities?

Answer

    1. Delhi was the warmest city as it has the highest positive temperature.

    2. Oslo was the coldest city as it has the largest negative temperature.

    3. The difference between the temperatures in these cities is 31˚C.

      From 19˚C down to 0˚C is 19˚C and then you need to go down a further 12˚C to get to −12˚C.

  1. Look at this bank statement.

    Figure 4 A bank statement
    View long description

    1. On which days was Sonia Cedar overdrawn, and by how much?

    2. How much money was withdrawn on 11 October?

    3. How much was added to the account on 15 October?

Answer

    1. The minus sign (−) indicates that the customer is overdrawn, i.e. owes money to the bank.

      The amount shows how much they owe. So Sonia Cedar was overdrawn on 11 October by £20 and by £50 on 21 October.

    2. £120 was withdrawn on 11 October.

      The customer had £100 in the account and must have withdrawn another £20 (i.e. £100 + £20 = £120 in total) in order to have a £20 overdraft.

    3. The customer owed £20 and is now £70 in credit, so £90 must have been added to the account.

You have now learned how to use all four operations and how to work with negative numbers. Every other mathematical concept hinges around what you have learnt so far; so once you are confident with these, you can do anything! Fractions, for example, are linked very closely to division and multiplication. Let’s put your newly found skills to good use in the next section, which deals with fractions.

Summary

In this section you have:

  • learned the two main contexts in which negative numbers arise in everyday life – money (or debt!) and temperature

  • practised working with negative numbers in these contexts.

◄Contents►Next: 4 Fractions

OpenLearn - Everyday Maths 2
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