Réponse :
Bonjour
Explications étape par étape :
Exercice 1
a) 18/8 - 25/100 = 18/8 - 5/20 = 18/8 X 2,5 - 5/20 = 45/20 - 5/20 = 40/20 = 4/2 = 2
b) 6/7 + 19/7 X 3 = la multiplication est prioritaire
6/7 + 57/3 = 6/7 X 3/3 + 57/3 X 7/7 = 18/21 + 399/21 = 417/21 = 139/7
c) 3/4 X 8/21 X 11/6 X 35/3 X 9/5
= 24/84 X 11/6 .............
24/84 , je simplifie = 2/7, je reprends
2/7 X 11/6 X 35/3 X 9/5
22/42 X 35/3 X ......
22/42, je simplifie = 11/21
11/21 X 35/3 X 9/5
385/63 , je simplifie = 55/9
55/9 X 9/5 = 495/45 = 99/9 = 11
d) (2/3 + 4/9) X 207/10 = (2/3 X 3/3 + 4/9) X 207/10 = (6/9 + 4/9) X 207/10
= 10/9 X 207/10 = 2 070/ 90 = 207/9 = 23
e) La somme de 17/2 et du produit de 6/16 X 24
17/2 + 6/16 X 24
17/2 + 144/16 = 17/2 X 8/8 + 144/16 = 136/16 + 144/16 = 280/16 = 70/4
