Bonjour,

3/5 + 8/20 = 12/20 + 8/20 = 20/20 = 1

3/5 - 8/20 =  12/20 - 8/20 = 4/20 = 1/5

19/17 + 25/51 = 57/51+ 25/51 = 82/51

19/17- 25/51 = 57/51- 25/51 = 32/51

1/25+ 3/150 = 1/25+ 1/50 = 2/50+ 1/50 = 3/50

1/25- 3/150 = 1/25 - 1/50 = 2/50- 1/50 = 1/50

5/19 + 6/95 = 25/95 + 6/95 = 31/95

5/19-6/95 = 25/95 - 6/95 = 19/95 =1/5

Réponse:

Bonjour

1) (3/5) × 4 + 8/20 b) (3/5) × 4 - 8/20

= 12/20 + 8/20 12/20 - 8/20

= 20/20 = 5/20

=1 =0,25

2) (19/17) × 3 + 25/51 b) (19/17) × 3 - 25/51

= 57/51 + 25/51 57/51 - 25/51

= 82/51 32/51

=1,61 0,63

3) (1/25) × 5 + 3/150 b) (1/25) × 5 - 3/150

= 6/150 + 3/150 = 6/150 - 3/150

= 9/150 = 3/150

=0,06 = 0,02

4) (5/19) × 5 + 6/95 b) (5/19) × 5 - 6/95

= 25/95 + 6/95 = 25/95 - 6/95

= 31/95 = 19/95

= 0,33 = 0,20

J'espère que j'ai pu t'aider ;)