脱式计算（带*号的要简算）19.8×0.54÷0.081*0.25×0.32×1.251.89+8.11×2.5*0.25×201-0.25*8.7×0.99*0.78+9.9×7.8．

Question

脱式计算（带*号的要简算）

19.8×0.54÷0.081	*0.25×0.32×1.25	1.89+8.11×2.5
*0.25×201-0.25	*8.7×0.99	*0.78+9.9×7.8．

Answer 1

（1）19.8×0.54÷0.081
=10.692÷0.081
=132；

（2）0.25×0.32×1.25
=0.25×（0.4×0.8）×1.25
=（0.25×0.4）×（0.8×1.25）
=0.1×0.1
=0.01；

（3）1.89+8.11×2.5
=1.89+20.275
=22.165；

（4）0.25×201-0.25
=0.25×（201-1）
=0.25×200
=50；

（5）8.7×0.99
=8.7×（1-0.01）
=8.7×1-8.7×0.01
=8.7-0.087
=8.613；

（6）0.78+9.9×7.8
=0.78+99×0.78
=0.78×（1+99）
=0.78×100
=78．