Réponse:
a) 2/1 -1/3+1/6-1/9
36/18-6/18+3/18- 2/18
(36-6+3-2)/18
31/18
b) 1/1+1/2+3/4-5/6
12/12+6/12+9/12- 10/12
(12+6+9-10)/12
17/12
c)4/3-(4/8+7/8)
4/3-11/8
32/24-33/23
-1/23
d) 4/3-7/5-(21/35-25/35)
4/3-7/5-(-4/35))
4/3-7/5+ 4/35
140/105-147/105+ 12/105
(140-147+12)/105
5/105
1/21