Réponse:
8/3 - 5/3 : 20/21 = 11/12
( 3 - 5/2 ) : ( 1 + 1/5 ) = 5/12
3/5 + 6/5 : 18/7 = 16/15
3 - 15/9 X 12/5 = - 1
1/5 - 3/5 : 12/7 = - 3/20
( 2 + 2/3 ) : ( 4/5 - 2/3 ) = 20
1 - ( 2/3 + 1/4 ) = 1/12
9/14 - 2/7 X 5 = - 12/14
1 - ( 1/4 + 3/4 X 4/5 ) = 3/20
