解:设这个数是X4/5X-62.5%X=0.350.8X-0.625X=0.350.175X=0.35X=0.35÷0.175X=2
0.35÷(5/4+62.5%)=0.35÷(1.25+0.625)=0.35÷1.875≈0.187
0.35/(5/4-62.5%)=0.56
设这个数是x,5/4x-62.5%x=0.35
f h c x h