| c) | Calcule après avoir simplifié l'écriture. |
| 26
+ (– 4) – (– 7) |
=
26 + (– 4) + 7 = 26 + 7 + (– 4) = [26 + 7] + (– 4) = 33 + (– 4) = 29 |
| –
17 – (+7) + (– 10) |
=
(– 17) + (– 7) + (– 10) = – 34 |
| 21
+ (– 5) + (– 6) – 7 |
=
21 + (– 5) + (– 6) + (– 7) = 21 + [(– 5) + (– 6) + (– 7)] = 21 + (– 18) = 3 |
| 9
– (– 5) + (– 4) – (+6) |
=
9 + 5 + (– 4) + (– 6) = [9 + 5] + [(– 4) + (– 6)] = 14 + (– 10) = 4 |
| (–
4) + (– 6) – (– 9) |
=
(– 4) + (– 6) + 9 = [(– 4) + (– 6)] + 9 = (– 10) + 9 = – 1 |
| 15
+ (– 25) + (– 8) + (– 7) |
=
15 + [(– 25) + (– 8) + (– 7)] = 15 + (– 40) = – 25 |
| 18
– (– 8) + (– 3) – (+6) |
=
18 + 8 + (– 3) + (– 6) = [18 + 8] + [(– 3) + (– 6)] = 26 + (– 9) = 17 |
| –
7 – (– 8) + (– 3) – (+6) |
=
– 7 + 8 + (– 3) + (– 6) = 8 + (– 7) + (– 3) + (– 6) = 8 + [(– 7) + (– 3) + (– 6)] = 8 + (– 16) = – 8 |
| 26
– 24 – (– 13) + 4 – (+10) |
=
26 + (– 24) + 13 + 4 + (– 10) = 26 + 13 + 4 + (– 24) + (– 10)] = [26 + 13 + 4] + [(– 24) + (– 10)] = 43 + (– 34) = 9 |
| 13
+ (– 7) – (– 5) + 7 – 13 + (– 5) |
=
13 + (– 7) + 5 + 7 + (– 13) + (– 5) = 13 + 5 + 7 + (– 7) + (– 13) + (– 5)] = 25 + (– 25) = 0 |