Question

15．簡算．
4.58÷6+5.42×$\frac{1}{6}$．
3.2×1.25×0.25       
76%×6.4+0.24×6.4．

Answer 1

分析 ①運用乘法分配律計算即可．
②運用乘法交換律和結(jié)合律計算．
③先把百分數(shù)變成小數(shù)，再用乘法分配律計算．

解答 解：①4.58÷6+5.42×$\frac{1}{6}$
=4.58×$\frac{1}{6}$+5.42×$\frac{1}{6}$
=（4.58+5.42）×$\frac{1}{6}$
=10×$\frac{1}{6}$
=$1\frac{2}{3}$

②3.2×1.25×0.25
=4×0.8×1.25×0.25
=（4×0.25）×（0.8×0.25）
=1×1
=1

③76%×6.4+0.24×6.4
=0.76×6.4+0.24×6.4
=（0.76+0.24）×6.4
=1×6.4
=6.4

點評 該題考查運算定律的靈活運用．