ex 41
a) 3/7=3×7/7×7=21/49
b)3/7+5/49=21/49+5/49=26/49
ex 42
a)1/2+1/4=3/8
b)5/6+5/12=15/12=5/4
c)13/14+5/7=23/14
d)3/4+5/24=23/24
e)6/7+2/35=32/35
f)11/81+1/9=20/81
