Bonjour
a. - 7/50 + 2/75
= (- 7 x 3) / (50 x 3) + (2 x 2) / (75 x 2)
= - 21/150 + 4/150
= - 17/150
b. 1/5 + - 2/3
= (1 x 3) / (5 x 3) - (2 x 5) / (3 x 5)
= 3/15 - 10/15
= - 7/15
c. 1/12 - 1/9
= (1 x 3) / (12 x 3) - (1 x 4) / (9 x 4)
= 3/36 - 4/36
= - 1/36
d. 4/18 + 5/27
= (4 x 3) / (18 x 3) + (5 x 2) / (27 x 2)
= 12/54 + 10/54
= 22/54
= (2 x 11) / (2 x 27)
= 11/27
e. 17/- 24 + (- 5/36)
= (- 17 x 3) / (24 x 3) - (5 x 2) / (36 x 2)
= - 51/72 - 10/72
= - 51/72
f. 3/16 - - 1/12
= (3 x 3) / (16 x 3) + (1 x 4) / (12 x 4)
= 9/48 + 4/48
= 13/48
g. 8/- 17 - (- 1/15)
= (- 8 x 15) /(17 x 15) + (1 x 17) / (15 x 17)
= - 120/255 + 17/255
= - 103/255
h. 2/5 + - 2/15 - 7/12
= (2 x 12) / (5 x 12) - (2 x 4) / (15 x 4) - (7 x 5) / (12 x 5)
= 24/60 - 8/60 - 35/60
= - 19/60
