Bonsoir
12)
A = 7/2 + 5/6 - 5/3
A = (7 x 3) / (2 x 3) + 5/6 - (5 x 2) / (3 x 2)
A = 21/6 + 5/6 - 10/6
A = 16/6
A = (2 x 8) / (2 x 3)
A = 8/3
B = 1 - 7/16 - 1/2
B = (1 x 16) / (1 x 16) - 7/16 - (1 x 8) / (2 x 8)
B = 16/16 - 7/16 - 8/16
B = 1/16
13)
A = 1/2 + 5/3
A = (1 x 3) / (2 x 3) + (5 x 2) / (3 x 2)
A = 3/6 + 10/6
A = 13/6
B = 3/4 + 2/5
B = (3 x 5) / (4 x 5) + (2 x 4) / (5 x 4)
B = 15/20 + 8/20
B = 23/20
C= 3/4 + 4/5
C = (3 x 5) / (4 x 5) + (4 x 4) / (5 x 4)
C = 15/20 + 16/20
C = 31/20
D = 5/6 + 9/4
D = (5 x 2) / (6 x 2) + (9 x 3) / (4 x 3)
D = 10/12 + 27/12
D = 37/12
E = 2/9 + 5/6
E = (2 x 2) / (9 x 2) + (5 x 3) / (6 x 3)
E = 4/18 + 15/18
E = 19/18
F = - 1/14 + 1/21
F = (1 x 3) / (14 x 3) + (1 x 2) / (21 x 2)
F = 3/42 + 2/42
F = 5/42.
