Verified answer

Bonsoir,

a + b

7/9 + 2/9 = 11/9

13/7 + 8/7 = 21/7 = 3

5/6 + 2/3 = 5/6 + 4/6 = 9/6 = 3/2

1/4 + 1/12 = 3/12 + 1/12 = 4/12 = 1/3

3/2 + 3/8 = 12/8 + 3/8 = 15/8

et

a - b

7/9 - 2/9 = 5/9

13/7 - 8/7 = 5/7

5/6 - 2/3 = 5/6 - 4/6 = 1/6

1/4 - 1/12 = 3/12 - 1/12 = 2/12 = 1/6

3/2 - 3/8 = 12/8 - 3/8 = 9/8

Donc :

               11/9                 3              3/2                1/3                15/8

                5/9                5/7           1/6                  1/6                 9/8  

Réponse :

1) 7/9 + 2/9 = 9/9 = 1

2) 13/7 + 8/7 =21/7 = 3

3) 5/6 + 2/3 = 5/6 +4/6 =9/6 = 3/2

4) 1/4 + 1/12 = 3/12 + 1/12 = 4/12 =1/3

5) 3/2 + 3/8 = 12/8 + 3/8 = 15/8

6) 7/9 - 2/9 = 5/9

7) 13/7 - 8/7 = 5/7

8) 5/6 - 2/3 = 5/6 - 4/6 = 1/6

9) 1/4 -1 /12 = 3/12 - 1/12 = 2/12= 1/6

10) 3/2-3/8= 12/8 - 3/8 = 9/8