計(jì)算,能簡(jiǎn)算的要簡(jiǎn)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(yùn)算的運(yùn)算順序和計(jì)算法則進(jìn)行計(jì)算;(1)運(yùn)用乘法分配律進(jìn)行簡(jiǎn)算;(3)變化0.32后運(yùn)用乘法結(jié)合律進(jìn)行簡(jiǎn)算;(6)運(yùn)用加法結(jié)合律進(jìn)行簡(jiǎn)算.
點(diǎn)評(píng):此題考查小數(shù)的四則混合運(yùn)算,細(xì)心計(jì)算,同時(shí)注意運(yùn)用定律進(jìn)行簡(jiǎn)算.