A=3/4+5/12 ; B=7/5-1/5x2/11 ; C=(1/5-1/10)x(7+7/2) En precisant toutes les etapes du calcul, ecris A,B et C sous la forme d'une fraction simplifiée le plus poss

A = 3/4 + 5/12

A = 3x3/4x3 + 5/12

A = 9/12 + 5/12

A = 14/12

A = 7/6

B = 7/5 - 1/5 x 2/11

B = 7/5 - 1x2/5x11

B = 7/5 - 2/55

B = 7x11/5x11 - 2/55

B = 77/55 - 2/55

B = 75/55

B = 15/11

C = (1/5 - 1/10) x (7 + 7/2)

C = (1x2/5x2 - 1/10) x (7x2/1x2 + 7/2)

C = (2/10 - 1/10) x (14/2 + 7/2)

C = 1/10 x 21/2

C = 1x21/10x2

C = 21/20