bonjour
35 x 12 = 35 x (10 + 2)
= (35 x 10) + (35 x 2) (distributivité)
= 350 + 70 = 420
27 x 101 = 27 x (100 + 1) = (27 x 100) + (27 x 1) = 27 x 100 + 27 = .. tu finis
57 x 99 = 57 x (100 - 1) = (57 x 100) - (57 x 1) = 57 x 100 - 57 = .. tu finis
17 x 13 = 17 x (10 + 3) = (17 x 10) + (17 x 3) =.. tu finis
je te laisse le dernier
