Bonsoir
Calculer et donner les résultats sous forme de fraction simplifiée le plus possible
a) 2/3 + (-5/6)
= (2 x 2) / (3 x 2) - 5/6
= 4/6 - 5/6
= - 1/6
b) -5/7 - 7/12
= (- 5 x 12) / (7 x 12) - (7 x 7) / (12 x 7)
= - 60/84 - 49/84
= - 109/84
c) 5/14 * -7/15
= - 35/210
= (35 x - 1) / (35 x 6)
= - 1/6
d) 1/2 : 1/4
= 1/2 x 4
= 4/2
= (2 x 2) / (2 x 1)
= 2
e) 3/20 + 5/12
= (3 x 3) / (20 x 3) + (5 x 5) / (12 x 5)
= 9/60 + 25/60
= 34/60
= (2 x 17) / (2 x 30)
= 17/30
f) - 17/13 + 2/3
= (- 17 x 3) / (13 x 3) + (2 x 13) / (3 x 13)
= - 51/39 + 26/39
= - 25/39
g) -72/15/ -4/3
= - 72/15 x - 3/4
= 216/60
= (12 x 18) / (12 x 5)
= 18/5
h) -3/15/5 - Je ne sais pas où est le signe divisé
- 3/15 : 5
= - 3/15 x 1/5
= - 3/75
= (3 x - 1) / (3 x 25)
= - 1/25
ou
- 3 : 15/5
= - 3 x 5/15
= - 15/15
= - 1
i) 3/4 * -6/9 * 26/7
= - 18/36 x 26/7
= - 468/252
= (36 x - 13) / (36 x 7)
= - 13/7.
