Exo 1 svp aidez moi. Svp merci

A = 5/7 + 6/7
A = 11/7

B = 15/11 - 3/11
B = 12/11

C = 21/18 - 2/3
C = 21/18 - 2 x 6 / 3 x 6
C = 21/18 - 12/18
C = 9/18
C =  9 x 1 / 9 x 2
C = 1/2

D = 63/10 - 301/100
D = 63 x 10 / 10 x 10 - 301/100
D = 630/100 - 301/100
D = 329/100

E = 2 - 5/9
E = 2 x 9 / 1 x 9 - 5/9
E = 18/9 - 5/9
E = 13/9

F = 3 + 20/7
F = 3 x 7 / 1 x 7 + 20/7
F = 21/7 + 20/7
F = 41/7

G = 3/7 + 26/21
G = 3 x 3 / 7 x 3 + 26/21
G = 9/21 + 26/2
G = 35/21
G = 7 x 5 / 7 x 3
G = 5/3

H = 5/42 + 9/14
H = 5/42 + 9 x 3 / 14 x 3
H = 5/42 + 27/42
H = 32/42
H = 2 x 16 / 2 x 21
H = 16/21