Question

5．用簡便方法計(jì)算下面各題．
43.6+9.8+6.4
17.3×0.25×8
2.31×1.5+1.5×7.69
3.75×10.1．

Answer 1

分析 ①先算43.6+6.4=50，再算50+9.8．
②先算后面的兩個(gè)數(shù)，再和第一個(gè)數(shù)相乘．
③用乘法分配律計(jì)算，ac+bc=（a+b）×c．
④把10.1變成10+0.1，再用乘法分配律計(jì)算．

解答 解：①43.6+9.8+6.4
=43.6+6.4+9.8
=50+9.8
=59.8

②17.3×0.25×8
=17.3×（0.25×8）
=17.3×2
=34.6

③2.31×1.5+1.5×7.69
=（2.31+7.69）×1.5
=10×1.5
=15

④3.75×10.1
=3.75×（10+0.1）
=3.75×10+3.75×0.1
=37.5+0.375
=37.875

點(diǎn)評 此題考查了學(xué)生對小數(shù)四則混合運(yùn)算題的計(jì)算能力，以及靈活巧算的能力．