Réponses

Meilleure réponse !
2014-09-26T06:27:45+02:00


Bonjour

1)

1/2+3/5

= 5/10 + 6/10

= 11/10


7/4-5/6= 21/12 - 10/12= 11/12
2-3/4
= 4/4 - 3/4= 1/4
2/3×5/7
= 10/21
3/2:7/6
= 3/2 x 6/7
3×5/11
= 15/11
7/4-3/4×5/4
= 7/4 - 15/16= 28/16 - 15/16= 13/16
2+2×5/6
= 2 + 10/6= 12/6 + 10/6= 22/6= 11/3
1-3/4+5/4
= 1 - 8/4= 4/4 - 8/4= -4/4= -1


2 ) Les 3/5 de 20 font: (20 x 3) / 5 = 60/5 = 12
donc les 3/5 de 20 font 12.
 75% de 140 font: (140 x 75) / 100 = 10500/100 = 105donc les 75% de 140 font: 105