aidee mwaa svp :) il faut detailler les calculs

D = 4/5 - 2
D = 4/5 - 2 x 5 / 1 x 5
D = 4/5 - 10/5
D = - 6/5

C = (2/8 - 3/16) : 3/10
C = (2 x 2 / 8 x 2 - 3/16) : 3/10
C = (4/16 - 3/16) : 3/10
C = 1/16 : 3/10
C = 1/16 x 10/3
C = 10/48
C = 2 x 5 / 2 x 24
C = 5/24

D = 5/4 + 2/5
       2 - 7/5
D = 5 x 5 / 4 x 5 + 2 x 4 / 5 x 4
           2 x 5 / 1 x 5 - 7/5
D = 25/20 + 8/20
       10/5 - 7/5
D = 33/20 : 3/5
D = 33/20 x 5/3
D = 165/60
D = 15 x 11 / 15 x 4
D = 11/4