Bonjour
a. 12/7 - 9/5
= (12 x 5) / (7 x 5) - (9 x 7) / (5 x 7)
= 60/35 - 63/35
= - 3/35
b. 2 + 1/4
= (2 x 4) / (1 x 4) + 1/4
= 8/4 + 1/4
= 9/4.
