Bonsoir,
A.
70 = 7 × 10 = 7 × 2 × 5
196 = 7 × 28 = 7 × 4 × 7 = 7 × 7 × 2 × 2
Donc 70 / 196 = 7 × 2 × 5 / 7 × 7 × 2 × 2 = 5 / 7 × 2
B.
52 = 2 x 26 = 2 × 2 × 13
204 = 2 × 102 = 2 × 2 × 51
Donc 52 / 204 = 2 × 2 × 13 / 2 × 2 × 51 = 13 / 51
C.
6672 = 2 × 3336 = 2 × 2 × 2 × 1668 = 2 × 2 × 2 × 2 × 834 = 2 × 2 × 2 × 2 × 2 × 417
= 2 × 2 × 2 × 2 × 2 × 3× 139
3684 = 2 × 1842 = 2 × 2 × 921 = 2 × 2 × 3 x 307
Donc 6672 / 3684 = 2 × 2 × 2 × 2 × 2 × 3 × 139 / 2 × 2 × 3 × 307 = 2 × 2 × 2 × 139 / 307
Bonne soirée
