考點:小數(shù)四則混合運算,運算定律與簡便運算
專題:運算順序及法則
分析:(1)先算除法,再算加法,最后算乘法;
(2)根據(jù)乘法交換律和結合律進行簡算;
(3)根據(jù)乘法分配律進行簡算;
(4)先算減法和加法,再算除法,最后算乘法;
(5)先算小括號里面的加法,再算中括號里面的除法和乘法,再算中括號里面的加法,最后算括號外面的除法.
解答:
解:(1)(1÷0.5+0.5÷1)×0.14
=(2+0.5)×0.14
=2.5×0.14
=0.35;
(2)0.4×0.4×1.5×2.5
=(0.4×1.5)×(0.4×2.5)
=0.6×1
=0.6;
(3)6.38×99+6.38
=6.38×(99+1)
=6.38×100
=638;
(4)(200-195.2)÷(8.37+1.23)×0.5
=4.8÷9.6×0.5
=0.5×0.5
=0.25;
(5)[5.4÷18+(41.47+38.53)×0.1]÷2.5
=[5.4÷18+80×0.1]÷2.5
=[0.3+8]÷2.5
=8.3÷2.5
=3.32.
點評:考查了運算定律與簡便運算,四則混合運算.注意運算順序和運算法則,靈活運用所學的運算定律簡便計算.