1624÷56 =29
29*56=1624
6分之5×7分之4 =20/42=10/21
10/21/(4/7)=5/6
8分之5-3分之1 =15/24-8/24=7/24
7/24+1/3=7/24+8/24=15/24=5/8
4.5×5.02=22.59
22.59/5.02=4.5