Aidez moi svp c pour demain

a = 3/4 - 1/20
a = 15/20 - 1/20 = 14/20 = 8/10 = 4/5

b = 13/18 - 2/3
b = 13/18 - 12/18
b = 1/18

c = 5/3 - 1/9
c = 15/9 - 1/9 = 14/9

d = 5/9 - 25/63
d = 35/63 - 25/63
d = 10/63

tu fais pareil pour les autres, tu mets sous dénominateur commun

Exo 4: A = 3/4 - 1/20
A = 3x5/4x5 - 1/20
A = 18/20 - 1/20
A = 18-1/20
A = 17/20

B = 13/18 - 2/3
B = 13/18 - 2x6/3x6
B = 13/18 - 12/18
B = 13-12/18
B = 1/18

C = 5/3 - 1/9
C = 5x3/3x3 - 1/9
C = 15/9 - 1/9
C = 15-1/9
C = 14/9

D = 5/9 - 25/63
D = 5x7/9x7 - 25/63
D = 35/63 - 25/63
D = 35-25/63
D = 10/63

E = 7/3 - 13/12
E = 7x4/3x4 - 13/12
E = 32/12 - 13/12
E = 32-13/12
E = 19/12

F = 7/5 - 13/15
F = 7x3/5x3 - 13/15
F = 21/15 - 13/15
F = 21-13/15
F = 8/15
Je te fais les suivant en dessous :)