計算,能簡算的要簡算.
1.8×5.46+1.8×4.54 16.38÷0.36-4.8 0.32×0.25×12.5
0.85+0.2×1.35 2.8÷3.5×4 2.64+8.67+1.33-1.64.
解:(1)1.8×5.46+1.8×4.54,
=(5.46+4.54)×1.8,
=10×1.8,
=18;
(2)16.38÷0.36-4.8,
=45.5-4.8,
=40.7;
(3)0.32×0.25×12.5,
=0.4×0.8×0.25×12.5,
=(0.4×0.25)×(0.8×12.5),
=0.1×10,
=1;
(4)0.85+0.2×1.35,
=0.85+0.27,
=1.12;
(5)2.8÷3.5×4,
=0.8×4,
=3.2;
(6)2.64+8.67+1.33-1.64,
=(2.64-1.64)+(8.67+1.33),
=1+10,
=11.
分析:(2)、(4)、(5)按四則混合運算的運算順序和計算法則進行計算;(1)運用乘法分配律進行簡算;(3)變化0.32后運用乘法結(jié)合律進行簡算;(6)運用加法結(jié)合律進行簡算.
點評:此題考查小數(shù)的四則混合運算,細心計算,同時注意運用定律進行簡算.