Réponse:
a) = 2×3/5×4=6/20=6÷2/20÷2=3/10
b) = 9/2 car les fractions se simplifient
c) = 18/50÷2=9/25 20/9×9/25=4/5
d) = 15×21=315 49×10=490 315÷490=315÷35/490÷35=9/14
e) 3/1×5/3 = 3×5/1×3=15/3
f) 240-240×35/100= 156
