Sagot :
Bonjour,
Exercice 4 :
13 × 99 = 13 × 100 - 1 × 13 = 13 × 100 - 13 = 1300 - 13 = 1287.
23 × 102 = 23 × 100 + 23 × 2 = 2300 + 46 = 2346.
Exercice 5 :
1\ 4 × (3 + 5)
= 4 × 8
= 32
2\ 4 × (3 + 5)
= 4 × 3 + 4 × 5
= 12 + 20
= 32
J'espère t'avoir aidé ^^