Question

数学题三道,要求简便计算1、0.7×5/8+0.3×3/82、1/4-1/10÷23、5/6×（2÷5/8-3）

Answer 1

1、0.7×5/8+0.3×3/8

= 0.1 x ( 35 /8 + 9/8 )

= 0. 1 x 44/8

= 0.1 x 5.5

= 0.55

2、1/4-1/10÷2

= 1/4 - 1/20

= ( 5-1) /20

= 4 / 20

= 5分之1

3、5/6×（2÷5/8-3）

= 5/6 x ( 2x 8/5 -3 )

= 5/6 x ( 16/5 - 3 )

= 5/6 x 16/5 - 5/6 x 3

= 8/3 - 5/2

= ( 16 - 15 ) / 6

= 6分之1