Bonjour
a. 42/75 - (-22/30)
= 42/75 + (2 x 11) / (2 x 15)
= 42/75 + 11/15
= 42/75 + (11 x 5) / (15 x 5)
= 42/75 + 55/75
= 97/75
b. 85/4 + 25/-5
= (85 x 5) / (4 x 5) - (25 x 4) / (5 x 4)
= 425/20 - 100/20
= 325/20
= (5 x 65) / (5 x 4)
= 65/4
c. -1/25-8
= - 1/25 - (8 x 25) / (1 x 25)
= - 1/25 - 200/25
= - 201/25
d. -14/27 + -5/108
= (- 14 x 4) / (27 x 4) - 5/108
= - 56/108 - 5/108
= - 61/108.
