Сравните дроби 1/7 и 4/21 , 3/5 и 8/15 , 4/7 и 16/28
1/7=(1*3)/(7*3)=3/21 3/21<4/21<br>1/7<4/21<br> 3/5=(3*3)/(5*3)=9/15 3/5>8/15 4/7=16/28 4/7=16/28