用自己喜欢的方法计算.51分之47÷31+51分之4×31分之1= 5分之1×37%+0.63×20%=

51分之47÷31+51分之4×31分之1
=47/51x1/31+4/51x1/31
=1/31x(47/51+4/51)
=1/31x1
=1/31

5分之1×37%+0.63×20%
=1/5x37%+63%x1/5
=1/5x(37%+63%)
=1/5x1
=1/5

7.5÷15%×25%
=7.5÷0.15x0.25
=(50x0.15)÷0.15x0.25
=50x0.25
=12.5
62.5%×12+8分之5×4
=5/8x12+5/8x4
=5/8x(12+4)
=5/8x16
=10