1 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1

2 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 Before we learn how to add and subtract negative numbers let us use the postman example: He delivers: cheques (positive) bills (negative) If they have been posted to us by mistake he can also take them back.

3 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 One day he delivers a £5 cheque and a £3 bill. We are £2 better off. £5£3 + +5+5-3+= 5 3–=2

4 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 Another day he delivers a £5 cheque and takes away a £6 cheque. We are £1 worse off. £5£6 – +5+5+6+6–= 5 6–=

5 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 Another day he delivers a £4 cheque and takes away a £3 bill. We are £7 better off. £4£3 – +4+4-3–= 4 3+=7

6 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 Another day he delivers a £6 cheque and a £4 cheque. We are £10 better off. £6£4 + +6+6+4+4+= 6 4+=10

7 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 He takes away a £5 cheque and brings a £4 cheque. We are £1 worse off. £5£4 + - 5+6+6+= 4+= -

8 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 He takes away a £2 cheque and brings a £2 bill. We are £4 worse off. £2 + - 2 += 2–=-4 -

9 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 He takes away a £5 cheque and a £7 bill. We are £2 better off. £5£7 – - 5-7–= - 5 7+=2 -

10 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 + ++ – –+ + –– – +–

11 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 What is 5 add -3 ? + ––

12 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 What is 5 subtract +6 ? – +–

13 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 What is 4 subtract -3 ? – –+

14 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 What is 6 add +4 ? + ++

15 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 What is -5 add +4 ? + ++

16 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 What is -2 subtract +2 ? – +–

17 © T Madas 0 1 2 3 4 5 6 7 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 What is -5 subtract -7 ? – –+

18 © T Madas 5 add +4 5 subtract -4 5 add -4 5 subtract +4 + ++ – –+ + –– – +–

19 © T Madas More Practice On Adding & Subtracting Negative Numbers

20 © T Madas + ++ – –+ + –– – +–

21 + ++ – –+ + –– – +–

22 + ++ – –+ + –– – +–

23 Quick Test On Adding & Subtracting Negative Numbers

24 © T Madas + ++ – –+ + –– – +–

25 + ++ – –+ + –– – +–

26 + ++ – –+ + –– – +–

27