a)
Calcule
en notant ton procédé. |
1000
– 102 |
= 1000
– (100 + 2) |
1000
– 120 |
=
1000 – (100 + 20) = 1000 – 100 – 20 = 900 – 20 = 880 |
1000
– 95 |
=
1000 – (100 –
5) = 1000 – 100 + 5 = 900 + 5 = 905 |
100
– 13 |
=
100 – (10 + 3) = 100 – 10 – 3 = 90 – 3 = 87 |
100
– 39 |
=
100 – (40
– 1) = 100 – 40 + 1 = 60 + 1 = 61 |
450
+ 99 |
=
450 + (100
– 1) = 450 + 100 – 1 = 550 – 1 = 549 |
250
+ 195 |
=
250 + (200 –
5) = 250 + 200 – 5 = 450 – 5 = 445 |
187
+ 102 |
=
187 + (100 + 2) = 187 + 100 + 2 = 287 + 2 = 289 |
288
+ 394 |
=
288 + (400 –
6) = 288 + 400 – 6 = 688 – 6 = 682 |
137
+ 198 |
=
137 + (200 –
2) = 137 + 200 – 2 = 337– 2 = 335 |