题目内容

10.
计算.
1÷($\frac{1}{5}$÷$\frac{1}{6}$)     

1÷($\frac{1}{3}$-$\frac{1}{4}$)    
$\frac{2}{13}$×$\frac{1}{3}$×39$\frac{5}{12}$+$\frac{3}{4}$+$\frac{5}{6}$
$\frac{4}{5}$×$\frac{7}{8}$+$\frac{7}{8}$×$\frac{1}{5}$$\frac{15}{17}$×5+$\frac{2}{17}$×5$\frac{3}{8}$-$\frac{3}{10}$×$\frac{5}{9}$35÷($\frac{6}{5}$÷$\frac{3}{7}$)     
$\frac{1}{4}$×6+$\frac{3}{8}$×6.

分析 (1)(2)(8)先算括号内的,再算括号外的;
(3)约分计算;
(4)通分计算;
(5)(6)(9)运用乘法分配律简算;
(7)先算乘法,再算减法.

解答 解:(1)1÷($\frac{1}{5}$÷$\frac{1}{6}$)
=1÷$\frac{6}{5}$
=$\frac{5}{6}$

(2)1÷($\frac{1}{3}$-$\frac{1}{4}$)
=1÷$\frac{1}{12}$
=12;

(3)$\frac{2}{13}$×$\frac{1}{3}$×39=2

(4)$\frac{5}{12}$+$\frac{3}{4}$+$\frac{5}{6}$
=$\frac{5}{12}$+$\frac{9}{12}$+$\frac{10}{12}$
=2

(5)$\frac{4}{5}$×$\frac{7}{8}$+$\frac{7}{8}$×$\frac{1}{5}$
=($\frac{4}{5}$+$\frac{1}{5}$)×$\frac{7}{8}$
=1×$\frac{7}{8}$
=$\frac{7}{8}$

(6)$\frac{15}{17}$×5+$\frac{2}{17}$×5
=($\frac{15}{17}$+$\frac{2}{17}$)×5
=1×5
=5

(7)$\frac{3}{8}$-$\frac{3}{10}$×$\frac{5}{9}$
=$\frac{3}{8}$-$\frac{1}{6}$
=$\frac{5}{24}$


(8)35÷($\frac{6}{5}$÷$\frac{3}{7}$)  
=35÷$\frac{14}{5}$
=35×$\frac{5}{14}$
=$\frac{25}{2}$

(9)$\frac{1}{4}$×6+$\frac{3}{8}$×6
=($\frac{1}{4}$+$\frac{3}{8}$)×6
=$\frac{5}{8}$×6
=$\frac{15}{4}$

点评 此题考查了分数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.

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