Bonjour vous pouvez m’aider pour les fractions svp merciii (si possible rédiger )

Bonjour,

1)

= 5/7

2)

12/27 + 5/27 = 17/27

3)

-9/6 + 14/6  = 5/6

4)

-8/12 - 9/12 = -17/12

5)

-21/75 +  55/75 =  34/75

6)

-45/90 +54/90+40/90 = 49/90

7)

4/7 -2/3 +5/7 =  12/21 -14/21 +15/21 = 13/21

8)

9/18 +6/18 +8/18 -15/18 = 8/18 = 4/9

9)

27/63- 35/63 -252/63 = -260/63