Bonjour,
a. 5/6 + - 1/3 = 5/6 - (1 x 2) / (3 x 2) = 5/6 - 2/6 = 3/6 = (3 x 1) / (3 x 2) = 1/2.
b. 7/9 - 1/- 27 = (7 x 3) / (9 x 3) + 1/27 = 21/27 + 1/27 = 22/27
c. - 8/5 + 23/50 = (- 8 x 10) / (5 x 10) + 23/50 = - 80/50 + 23/50 = - 57/50
d. 45/15 - 7/3 = 45/15 - (7 x 5) / (3 x 5) = 45/15 - 35/15 = 10/15 = (5 x 2) / (5 x 3) = 2/3
e. 4/11 + 2 = 4/11 + (2 x 11) / (1 x 11) = 4/11 + 22/11 = 26/11
f. 8/- 91 + - 1/7 = - 8/91 - (1 x 13)/ (7 x 13) = - 8/91 - 13/91 = - 21/91
g. 5/2 - - 45/4 + 2/8 = (5 x 4) / (2 x 4) + (45 x 2) / (4 x 2) + 2/8 = 20/8 + 90/8 + 2/8 = 112/8 = (8 x 14) / (8 x 1) = 14
h.4 - 5/- 49 + (- 8/7) = (4 x 49) / (1 x 49) + 5/49 - (8 x 7) / (7 x 7) = 196/49 + 5/49 - 56/49 = 145/49
i. - 7/50 + 7/75 = (- 7 x 3) / (50 x 3) + (7 x 2) / (75 x 2) = - 21/150 + 14/150 = - 7/150
j. 1/5 + - 2/3 = (1 x 3) / (5 x 3) - (2 x 5) / (3 x 5) = 3/15 - 10/15 = - 7/15
k. 1/12 - 1/9 = (1 x 3) / (12 x 3) - (1 x 4) / (9 x 4) = 3/36 - 4/36 = - 1/36
l. 4/18 + 5/27 = (4 x 6) / (18 x 6) + (5 x 4) / (27 x 4) = 24/108 + 20/108 = 44/108 = (4 x 11) / (4 x 27) = 11/27
m. 17/- 24 + (- 5/36) = (- 17 x 3) / (24 x 3) - (5 x 2) / (36 x 2) = - 51/72 - 1072 = - 41/72
n. 3/16 - 1/12 = (3 x 3)/ (16 x 3) - (1 x 4) / (12 x 4) = 9/48 - 4/48 = 5/48
o. 8/- 17 - (- 1/15) = (- 8 x 15) / (17 x 15) + (1 x 17) / (15 x 17) = - 120/255 + 17/255 = - 193/255
