REPONSES.

Exercice n°1
438 214 + 673 + 2813 = 441 700
904 + 38 526 + 47 = 39 477

Exercice n°3
1 245,28 + 314, 73 + 64,35 = 2624,36
21,8 + 618,47 + 9,376 = 649,646

Exercice n°4
738,48 – 521,26= 217,22
586,42 – 37,27 = 549,15
478,2 – 97,371 =380,829