Question

口算．我最棒． 4.2÷0.2=	8.3×0.1=	3.5+6.5=	0.5×0.8=
71.5-21.5=	9.3÷0.31=	10×0.1×100=	1.62÷0.19≈
12.5×2.5×4=	4.81×0.21≈	5.02×3.98≈	4.81÷0.21≈

Answer 1

考點(diǎn)：小數(shù)乘法,數(shù)的估算,小數(shù)除法

專(zhuān)題：計(jì)算題

分析：根據(jù)四則運(yùn)算的計(jì)算法則計(jì)算即可求解．注意12.5×2.5×4根據(jù)乘法結(jié)合律計(jì)算，根據(jù)四舍五入法求近似數(shù)．

解答： 解：

4.2÷0.2=21	8.3×0.1=0.83	3.5+6.5=10	0.5×0.8=0.4
71.5-21.5=50	9.3÷0.31=30	10×0.1×100=100	1.62÷0.19≈8
12.5×2.5×4=125	4.81×0.21≈1	5.02×3.98≈20	4.81÷0.21≈24

點(diǎn)評(píng)：考查了四則運(yùn)算，關(guān)鍵是熟練掌握計(jì)算法則正確進(jìn)行計(jì)算．