第70页 - 亮点给力提优课时作业本五年级数学江苏版

1

9

1

6

1

18

$\frac{1} {3}+\frac{2} {9} = \frac{5} {9}$

$答：文艺类书和工具类书占了书橱面积$

$的\frac {5}{9}$

$=\frac {14}{9}-\frac {4}{6}$

$=\frac {14}{9}-\frac {6}{9}$

$=\frac {8}{9}$

$=2-\frac {17}{25}+\frac {7}{15}-\frac {8}{25}$

$=2-(\frac {17}{25}+\frac {8}{25})+\frac {7}{15}$

$=2-1+\frac {7}{15}$

$=1\frac {7}{15}$

$=\frac {4}{7}-\frac {3}{7}+\frac {1}{14}$

$=\frac {1}{7}+\frac {1}{14}$

$=\frac {3}{14}$

$=(\frac {16}{11}-\frac {5}{11})+(\frac {5}{7}+\frac {2}{7})$

$=1+1$

$=2$

$1−\frac{1} {3}-\frac{2} {5} = \frac{4} {15}$

$答：还剩下这条路的\frac {4}{15}没有修。$

$\frac{1} {2} + \frac{1} {6} = \frac{2} {3}$

$答：这瓶可乐少了\frac {2}{3}。$

④

$\frac {3}{8}$

$\frac {1}{2}$

$\frac {7}{8}$

②

$\frac {1}{2}$

$\frac {1}{4}$