分析:①12.5×4.37×0.8,運(yùn)用乘法交換律和結(jié)合律簡算;
②13.7×4.3+13.7×5.7,運(yùn)用乘法分配律簡算;
③28.1×0.35-0.35×8.1,運(yùn)用乘法分配律簡算;
④4.23×99+4.23,運(yùn)用乘法分配律簡算;
⑤5.37÷0.4÷2.5,根據(jù)除法的運(yùn)算性質(zhì)簡算;
⑥(6.3+3.9)÷0.3,根據(jù)除法的運(yùn)算性質(zhì)簡算;
⑦7.6÷8+2.4÷8,根據(jù)除法的運(yùn)算性質(zhì)簡算;
⑧0.42÷35,根據(jù)除法的運(yùn)算性質(zhì)簡算.
解答:解:①12.5×4.37×0.8
=(12.5×0.8)×4.37
=10×4.37
=43.7;
②13.7×4.3+13.7×5.7
=13.7×(4.3+5.7)
=13.7×10
=137;
③28.1×0.35-0.35×8.1
=(28.1-8.1)×0.35
=20×0.35
=7;
④4.23×99+4.23
=4.23×(99+1)
=4.23×100
=423;
⑤5.37÷0.4÷2.5
=5.37÷(0.4×2.5)
=5.37÷1
=5.37;
⑥(6.3+3.9)÷0.3
=6.3÷0.3+3.9÷0.3
=21+13
=34;
⑦7.6÷8+2.4÷8
=(7.6+2.4)÷8
=10÷8
=1.25;
⑧0.42÷35
=0.42÷7÷5
=0.06÷5
=0.012.
點(diǎn)評(píng):此題考查的目的是理解掌握乘法的運(yùn)算定律和除法的運(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.