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Activity 56
Evaluate each of the following and give an example from everyday life to illustrate the sum (e.g. Thomas’s piggy bank).
(a) −4 − 6
(b) 3 + −5
(c) −4 + −7
(d) −5 + 8
Answer
(a) −4 − 6 = −10.
If you have an overdraft of £4 and take out £6 you have an overdraft of £10.
(b) 3 + −5 = 3 − 5 = −2.
Thomas’s bank has £3 plus a £5 IOU, which is equivalent to a £2 IOU.
(c) −4 + −7 = −4 − 7 = −11.
A debit of £4 plus a debit of £7 is equivalent to a debit of £11.
(d) −5 + 8 = 3.
An overdraft of £5 plus a deposit of £8 results in a balance of £3.