Question

10．怎樣算簡便就怎樣算．
$\frac{7}{10}$×$\frac{1}{6}$+$\frac{3}{10}$÷6                        
 $\frac{7}{13}$×$\frac{3}{4}$+$\frac{3}{4}$×$\frac{6}{13}$
24×$\frac{5}{7}$×$\frac{7}{12}$                           
（$\frac{2}{3}$+$\frac{1}{6}$）×24．

Answer 1

分析 ①$\frac{7}{10}$×$\frac{1}{6}$+$\frac{3}{10}$÷6，把除數(shù)轉(zhuǎn)化為乘它的倒數(shù)，再運(yùn)用乘法分配律簡算；                   
②$\frac{7}{13}$×$\frac{3}{4}$+$\frac{3}{4}$×$\frac{6}{13}$，運(yùn)用乘法分配律簡算；
③24×$\frac{5}{7}$×$\frac{7}{12}$，運(yùn)用乘法交換律和結(jié)合律簡算；                          
④（$\frac{2}{3}$+$\frac{1}{6}$）×24，運(yùn)用乘法分配律簡算．

解答 解：①$\frac{7}{10}$×$\frac{1}{6}$+$\frac{3}{10}$÷6      
=$\frac{7}{10}×\frac{1}{6}+\frac{3}{10}×\frac{1}{6}$
=（$\frac{7}{10}+\frac{3}{10}$）×$\frac{1}{6}$
=$1×\frac{1}{6}$
=$\frac{1}{6}$；
                  
②$\frac{7}{13}$×$\frac{3}{4}$+$\frac{3}{4}$×$\frac{6}{13}$
=（$\frac{7}{13}+\frac{6}{13}$）×$\frac{3}{4}$
=$1×\frac{3}{4}$
=$\frac{3}{4}$；

③24×$\frac{5}{7}$×$\frac{7}{12}$     
=$24×\frac{7}{12}×\frac{5}{7}$
=$14×\frac{5}{7}$
=10；
                      
④（$\frac{2}{3}$+$\frac{1}{6}$）×24
=$\frac{2}{3}×24+\frac{1}{6}×24$
=16+4
=20．

點(diǎn)評 此題考查的目的是理解掌握法四則混合運(yùn)算的順序以及他們的計(jì)算法則，并且能夠靈活選擇簡便方法進(jìn)行計(jì)算．