Bonjour
1)
1- PGCD (406 ; 696)
Selon la méthode d'Euclide :
696 = 1 x 406 + 290
406 = 1 x 290 + 116
290 = 2 x 116 + 58
116 = 2 x 58 + 0
Le PGCD est égal au dernier reste non nul : 58
2- 406/696 = (58 x 7) / (58 x 12) = 7/12.
2)
A = 7/4 + 11/2
A = 7/4 + (11 x 2) / (2 x 2)
A = 7/4 + 22/4
A = 29/4
B = 3/11 - 5/2
B = (3 x 2) / (11 x 2) - (5 x 11) / (2 x 11)
B = 6/22 - 11/22
B = - 5/22
C = 5/42 x 21/4
C = 105/168
C = (21 x 5) / (21 x 8)
C = 5/8
D = 2/3 x 15
D = 30/3
D = (3 x 10) / (3 x 1)
D = 10
