calculer les fractions ci dessous en detaillant les etapes de calcul et en donnant le resultat sous la forme le plus simple possible fractions : A=1sur5-7sur5x2

A = 1/5 - 7/5 x 2/3
A = 6/5 x 2/3
A = 6/5 x 2/3
A = 12/15
A = 4/5

B = (4/3 - 2/9) x 5/4
B = (12/9 - 2/9) x 5/4
B = 10/9 x 5/4
B = 50/36
B = 25/18
              
C = 13/5 - 8/25 : 16/35
C = 65/25 - 8/25 : 16/35
C = 57/25 : 16/35
C = 57/25 x 35/16
C = 1995/400
C = 399/80
              
D = 9/5 x 7/8 - 3/4 : 5/7
D = 63/40 -30/40 : 5/7
D = 33/40 : 5/7
D = 33/40 x 7/5
D = 231/200

1/5-7/5*2/3=1/5-14/15=(3*1/5*3)-14/15=-11/15
B=(4/3-2/9)*5/4=[(3*4/3*3)-2/9]*5/4=(*5/4=10/9*5/4=(12/9-2/9)*5/4=10/9*5/4=50/36=25/18
C=13/5-8/25:16/35=13*5/5-8/25:16/35=65-8/25:16/35=57/25:16/35=57/25:35/16=399/80
D=9/5*7/8-3/4:5/7=63/40-3/4:5/7=63/40-3*10/40:5/7=63-30/40:5/7=33/40*7/5=231/200