分析:0.56×0.125,根據(jù)積不變的性質(zhì),一個(gè)因數(shù)擴(kuò)大幾倍,另一個(gè)因數(shù)縮小相同的倍數(shù).積不變.
24÷0.125,4÷0.25,根據(jù)商不變的性質(zhì)簡算.
48×0.25,把48拆分為:12×4,運(yùn)用乘法結(jié)合律簡算.
6.42×99,運(yùn)用乘法分配律簡算.
18.65-3.7+1.35-16.3,根據(jù)加、減法的運(yùn)算性質(zhì)簡算.
(16.5×24+24×7.5)÷0.6,運(yùn)用乘法分配律簡算.
10.5×60×5×8,運(yùn)用乘法交換律和結(jié)合律簡算.
87.5×305-87.5-4×87.5,運(yùn)用乘法分配律簡算.
93÷0.31÷3,根據(jù)除法的運(yùn)算性質(zhì)簡算.
15.8-4.72-6.28,根據(jù)減法的運(yùn)算性質(zhì)簡算.
解答:解:0.56×0.125
=(0.56÷8)×(0.125×8)
=0.07×1
=0.07;
24÷0.125
=(24×8)÷(0.125×8)
=192÷1
=192;
48×0.25=12×(4×0.25)
=12×1
=12;
4÷0.25
=(4×4)÷(0.25×4)
=16÷1
=16;
6.42×99
=6.42×(100-1)
=6.42×100-6.42
=642-6.42
=635.58;
18.65-3.7+1.35-16.3
=18.65+1.35-(3.7+16.3)
=20-20
=0;
(16.5×24+24×7.5)÷0.6
=(16.5+7.5)×24÷0.6
=24×24÷0.6
=576÷0.6
=960;
10.5×60×5×8
=(10.5×60)×(5×8)
=630×40
=25200;
87.5×305-87.5-4×87.5
=87.5×(305-1-4)
=87.5×300
=26250;
93÷0.31÷3
=93÷(0.31×3)
=93÷0.93
=100;
15.8-4.72-6.28
=15.8-(4.72+6.28)
=15.8-11
=4.8.
點(diǎn)評:此題考查的目的是理解掌握乘法的運(yùn)算定律,加減法、乘法、除法的運(yùn)算性質(zhì),并且能夠靈活運(yùn)用這些運(yùn)算定律和運(yùn)算性質(zhì)進(jìn)行簡便計(jì)算.