Réponse :
0.8 = ....../25 ⇔ 0.8 = a/25 ⇔ a = 25 x 0.8 = 20 donc 0.8 = 20/25
1.8 = 27/..... ⇔ 1.8 = 27/b ⇔ b = 27/1.8 = 15 donc 1.8 = 27/15
0.4 x ...../...... = 1/3 ⇔ 0.4 x a/b = 1/3 ⇔ b = 1.2 a donc 0.4 x a/1.2a = 1/3
⇔ 0.4 x 10/12 = 1/3
6+4/7 = 42/7+4/7 = 46/7
13 - 5/4 = 52/4 - 5/4 = 47/4
4/7 + 12/14 = 4/7 + 6/7 = 10/7
3/5 + 0.9 = 3/5 + 9/10 = 6/10+9/10 = 15/10 = 3/2
tu fais le reste
Explications étape par étape
