1. 计算。
$10÷ \frac{5}{9}+\frac{1}{6}× 4$ $\frac{7}{9}÷ \frac{11}{5}+\frac{2}{9}× \frac{5}{11}$ $24× (\frac{7}{12}× \frac{5}{48})$
$\frac{2}{15}× \frac{3}{4}+\frac{3}{4}× \frac{13}{15}$ $\frac{1}{9}÷ (\frac{2}{5}× \frac{5}{2})$ $\frac{6}{7}× 5+\frac{6}{7}$
$10÷ \frac{5}{9}+\frac{1}{6}× 4$ $\frac{7}{9}÷ \frac{11}{5}+\frac{2}{9}× \frac{5}{11}$ $24× (\frac{7}{12}× \frac{5}{48})$
$\frac{2}{15}× \frac{3}{4}+\frac{3}{4}× \frac{13}{15}$ $\frac{1}{9}÷ (\frac{2}{5}× \frac{5}{2})$ $\frac{6}{7}× 5+\frac{6}{7}$
答案
$\frac{56}{3}$ $\frac{5}{11}$ $\frac{35}{24}$ $\frac{3}{4}$ $\frac{1}{9}$ $\frac{36}{7}$
解析
$10÷ \frac{5}{9}+\frac{1}{6}× 4$
$=10× \frac{9}{5}+\frac{2}{3}$
$=18+\frac{2}{3}$
$=\frac{56}{3}$
$\frac{7}{9}÷ \frac{11}{5}+\frac{2}{9}× \frac{5}{11}$
$=\frac{7}{9}× \frac{5}{11}+\frac{2}{9}× \frac{5}{11}$
$=(\frac{7}{9}+\frac{2}{9})× \frac{5}{11}$
$=1× \frac{5}{11}$
$=\frac{5}{11}$
$24× (\frac{7}{12}× \frac{5}{48})$
$=24× \frac{7}{12}× \frac{5}{48}$
$=14× \frac{5}{48}$
$=\frac{35}{24}$
$\frac{2}{15}× \frac{3}{4}+\frac{3}{4}× \frac{13}{15}$
$=(\frac{2}{15}+\frac{13}{15})× \frac{3}{4}$
$=1× \frac{3}{4}$
$=\frac{3}{4}$
$\frac{1}{9}÷ (\frac{2}{5}× \frac{5}{2})$
$=\frac{1}{9}÷ 1$
$=\frac{1}{9}$
$\frac{6}{7}× 5+\frac{6}{7}$
$=\frac{6}{7}× (5 + 1)$
$=\frac{6}{7}× 6$
$=\frac{36}{7}$
$=10× \frac{9}{5}+\frac{2}{3}$
$=18+\frac{2}{3}$
$=\frac{56}{3}$
$\frac{7}{9}÷ \frac{11}{5}+\frac{2}{9}× \frac{5}{11}$
$=\frac{7}{9}× \frac{5}{11}+\frac{2}{9}× \frac{5}{11}$
$=(\frac{7}{9}+\frac{2}{9})× \frac{5}{11}$
$=1× \frac{5}{11}$
$=\frac{5}{11}$
$24× (\frac{7}{12}× \frac{5}{48})$
$=24× \frac{7}{12}× \frac{5}{48}$
$=14× \frac{5}{48}$
$=\frac{35}{24}$
$\frac{2}{15}× \frac{3}{4}+\frac{3}{4}× \frac{13}{15}$
$=(\frac{2}{15}+\frac{13}{15})× \frac{3}{4}$
$=1× \frac{3}{4}$
$=\frac{3}{4}$
$\frac{1}{9}÷ (\frac{2}{5}× \frac{5}{2})$
$=\frac{1}{9}÷ 1$
$=\frac{1}{9}$
$\frac{6}{7}× 5+\frac{6}{7}$
$=\frac{6}{7}× (5 + 1)$
$=\frac{6}{7}× 6$
$=\frac{36}{7}$
2. 小红折了 120 个幸运星,______,小明折了多少个幸运星?根据这道题的已知条件和问题,找出下列算式和横线上应填语句的对应关系,用线段连起来。
(1)$120× (1+\frac{2}{3})$
(2)$120÷ \frac{2}{3}$
(3)$120× \frac{2}{3}$
(4)$120× (1-\frac{2}{3})$
(1)$120× (1+\frac{2}{3})$
d
a. 小明是小红的$\frac{2}{3}$(2)$120÷ \frac{2}{3}$
c
b. 小明比小红少$\frac{2}{3}$(3)$120× \frac{2}{3}$
a
c. 小红是小明的$\frac{2}{3}$(4)$120× (1-\frac{2}{3})$
b
d. 小明比小红多$\frac{2}{3}$答案
(1)—d
(2)—c
(3)—a
(4)—b
(2)—c
(3)—a
(4)—b
3. 算一算,比一比。
(1)5 米剪去它的$\frac{1}{5}$,还剩几米?

(2)5 米剪去$\frac{1}{5}$米,还剩几米?
(1)5 米剪去它的$\frac{1}{5}$,还剩几米?
(2)5 米剪去$\frac{1}{5}$米,还剩几米?
答案
(1)4米
(2)$4\frac{4}{5}$米
(2)$4\frac{4}{5}$米
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