Question

7．脫式計(jì)算．（能簡算的要簡算）
0.25×9.45×40                     0.37×9+0.37
6.8×4.5÷0.85                     48.96+51.04÷2.9．

Answer 1

分析 ①運(yùn)用乘法交換律和乘法結(jié)合律可進(jìn)行簡便計(jì)算；
②運(yùn)用乘法分配律可進(jìn)行簡便運(yùn)算；
③運(yùn)用乘法交換律和結(jié)合律可進(jìn)行簡便計(jì)算；
④按照四則運(yùn)算法則，首先計(jì)算除法，然后再計(jì)算加法，計(jì)算即可．

解答 解：①0.25×9.45×40
=0.25×40×9.45
=10×9.45
=94.5

②0.37×9+0.37
=0.37×（9+1）
=0.37×10
=3.7

③6.8×4.5÷0.85
=6.8÷0.85×4.5
=8×4.5
=36

④48.96+51.04÷2.9
=48.96+17.6
=66.56

點(diǎn)評 考查了運(yùn)算定律與簡便運(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．