Bonjour,
1)
25/75 = (25 x 1) / (25 x 3) = 1/3
52/78 = (26 x 2) / (26 x 3) = 2/3
- 64/- 16 = (16 x 4) / (16 x 1) = 4
- 1,5/ 7,5 = (- 1,5 x 10) / (7,5 x 10) = - 15/75 = (15 x - 1) / (15 x 5) = - 1/5
2)
A = 5/4 + 7/8
A = (5 x 2) / (4 x 2) + 7/8
A = 10/8 + 7/8
A = 17/8
B = 3/2 - 1/4
B = (3 x 2) / (2 x 2) - 1/4
B = 6/4 - 1/4
B = 5/4
C = 4 + 3/2
C = (4 x 2) / (1 x 2) + 3/2
C = 8/2 + 3/2
C = 11/2
D = 27/7 - 3
D = 27/7 - (3 x 7) / (1 x 7)
D = 27/7 - 21/7
D = 6/7
E = 4/3 x 6/8
E = 24/32
E = (8 x 3) / (8 x 4)
E = 3/4
F = 12/5 x 12/4
F = 144/20
F = (4 x 36) / (4 x 5)
F = 36/5
G = 5/7 x 3/25
G = 15/175
G = (5 x 3) / (5 x 35)
G = 3/35.
