Répondre :
a) 72/56 = 8x9/8x7=9/7
b) 30/400= 3x10/40x10= 3/40
c) 24/16= 3x8/2x8= 3/2
d) 49/42= 7x7/7x6=7/6
2a) 3(7/5)+14/15= 21/15+14/15= 35/15= 7x5/3x5=7/3
2b) 7/5x3/4= (7x3)/(5x4)= 21/20
b) 30/400= 3x10/40x10= 3/40
c) 24/16= 3x8/2x8= 3/2
d) 49/42= 7x7/7x6=7/6
2a) 3(7/5)+14/15= 21/15+14/15= 35/15= 7x5/3x5=7/3
2b) 7/5x3/4= (7x3)/(5x4)= 21/20