1/2 - 1/7 3/5 - 4/15
1/2 - 1/7=5/14
3/5 - 4/15=1/3
1) (1/2)-(1/7)=((1×7)-(1×2))/14=(7-2)/14=5/14 2) (3/5)-(4/15)=((3×3)-4)/15=(9-4)/15=5/15=1/3