Faire les exercices 18 19 et 20 Merci ♡ 20 points offerts ♡

18)
A = 14/9 + 4/9
A = 18/9
A = 9 x 2 / 9 x 1
A = 2

B = 25/4 + 7/4
B = 32/4
B = 4 x 8 / 4 x 1
B = 8

C = 31/15 - 11/15
C = 20/15
C = 5 x 4 / 5 x 3
C = 4/3

D = 25/6 - 21/6
D = 4/6
D = 2 x 2 / 2 x 3
D = 2/3

19)
A = 16/21 + 26/21
A = 42/21
A = 21 x 2 / 21 x 1
A = 2

B = 3/15 + 2/15
B = 5/15
B = 5 x 1 / 5 x 3
B = 1/3

C = 46/35 - 25/35
C = 21/35
C = 7 x 3 / 7 x 5
C = 3/5

D = 17/21 - 10/21
D = 7/21
D = 7 x 1 / 7 x 3
D = 1/3

20)
a) 9/17 + 14/17 = 23/17
b) 2,6/1,9 + 13,4/1,9 = 16/1,9
c) 24/23 - 9/23 = 15/23
d) 31,7/1,7 - 10/1,7 = 21/1,7