分析:(1)78×10.1,運(yùn)用乘法分配律進(jìn)行簡算;
(2)(78.6-18.6÷0.31)×1.5,根據(jù)小數(shù)四則混合運(yùn)算的順序,按照小數(shù)四則運(yùn)算的計(jì)算法則進(jìn)行簡算;
(3)6.2×66.7+66.7×4.8-66.7,運(yùn)用乘法分配律進(jìn)行簡算;
(4)(5.9+5.9+5.9+5.9)×0.25,首先根據(jù)乘法的意義,將原式轉(zhuǎn)化為:9.5×4×0.25,再運(yùn)用乘法結(jié)合律進(jìn)行簡算.
解答:解:(1)78×10.1,
=78×10+78×0.1,
=780+7.8,
=787.8;
(2)(78.6-18.6÷0.31)×1.5,
=(78.6-60)×1.5,
=18.6×1.5,
=27.9;
(3)6.2×66.7+66.7×4.8-66.7,
=(6.2+4.8-1)×66.7,
=10×66.7,
=667;
(4)(5.9+5.9+5.9+5.9)×0.25,
=9.5×(4×0.25),
=9.5×1,
=9.5.
點(diǎn)評:此題主要考查小數(shù)四則混合運(yùn)算,注意運(yùn)算順序和運(yùn)算法則,靈活運(yùn)用所學(xué)的運(yùn)算律簡便計(jì)算.