Bonjour
2/7-7 = 2/7 - (7 x 7) / (1 x 7) = 2/7 - 49/7 = - 47/7
B 13/6+5/6 = 18/6 = (6 x 3) / (6 x 1) = 3
C 11/10+3/2 = 11/10 + (3 x 5) / (2 x 5) = 11/10 + 15/10 = 26/10 = (2 x 13) / (2 x 5) = 13/5
D -8/13-(1/4-2/7)
= - 8/13 - [(1 x 7) / (4 x 7) - (2 x 4) / (7x 4)]
= - 8/13 - (7/28 - 8/28)
= 8/13 - (- 1/28)
= 8/13 + 1/28
= (8 x 28) / (13 x 28) + (1 x 13) / (28 x 13)
= 224/364 + 13/364
= 237/364.
