1/2是3/4的几分之几
1/2÷3/4=1/2×4/3=2/3
2/3是8/9的几分之几
2/3÷8/9=2/3×9/8=3/4
7/8是1/4的几倍
7/8÷1/4=7/8×4=7/2
4/5是1/4的几倍
4/5÷1/4=4/5×4=16/5