quelqu’un pourrait m’aider pour cette exercice (exo 23)?

Réponse :

bonsoir

3/9 + 5/2  = 6/18 + 45/18 = 51/18 = 17/6

6/7 - 2/3 = 18/21 - 14/21 = 4 /21

7/4 - 9/5  = 35/20 - 36/20 = - 1 /20

3/8 + 1/7 = 21/56 + 8/56 = 29/56

- 7/3 - 1 /4 = - 28/12 - 3/12 = - 31 /12

2/11 - 3/10 = 20/110 - 33/110 = - 13 /110

exercice 22

a. 42

b. 1/6 + 1/7 = 7/42 + 6/42 = 13/42 (on met au dénominateur commun)

c. 5/6 - 9/7 = 35/42 - 54/42 = -19/42  (on met au dénominateur commun)

d. (1/6 + 1/7) - (5/6 - 9/7) = 13/42 - (-19/42) = 13/42 + 19/42 = 16/21

exercice 23

a. 3/9 + 5/2 = 6/18 + 45/18 = 17/6

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