早教吧 育儿知识 作业答案 考试题库 百科 知识分享

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.

题目详情
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.
▼优质解答
答案和解析
(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.