Réponses

2012-09-11T21:00:56+02:00

a) ( 7/7-1/7):12/5=6/7:12/5=6/7*5/12=(6*5)/(7*6*2)=5/14

b) (5/20-4/20)*(63/9+37/9)=(1/20)*(100/9)=1/20*9/100=10/2000=1/200

c) 3/4+1/2*(2/3-3/3)=3/4+1/2*(-1/3)=3/4-1/6=9/12-2/12=7/12

 

voila !