Réponse :
Explications étape par étape
2)
a. 3/9 + 5/2 = 6/18 + 45/18 = 51/18
b. 6/7 - 2/3 = 18/21 - 14/21 = 4/21
c. 7/4-9/5 = 35/20 - 36/20 = 1/20
d. 3/8 + 1/7 = 21/56 + 8/56 = 29/56
e. -7/3 + -1/4 = -28/12 + -3/12 = -31/12
f. 2/11 - 3/10 = 20/110 - 33/110 = -13/110
3)
1. 5/6 + 3/14 = 5*3/6*7 + 3*7/14*3 = 15/42 + 21/42 = 36/42
2. 36/42 = 12/14 = 6/7
4)
a. 1/2 + 7/5 = 5/10 + 14/10 = 19/10
b. 8/7 - 7/12 = 96/84 - 49/84 = 47/84
c. 2/23 - 11/10 = 20/230 - 253/230 = -233/230
d. -3/4 - 7/9 = -27/36 - 28/36 = -55/36
