Bonjour pouvais vous Maider svp ex de 4e

bonjour


A = 7/3 - 5 /9 
A = 21/9 - 5/9 = 16/9 

B = 9/5 - 14/55
b = 99/55 - 14/55 = 85/55 = 17/11

C = ( 2/9 + 1/6) :  5/12
c =  ( 4/18 + 3/18) : 5/12
C = 7/18 x 1/5 
C = 7/90