1. 在$\bigcirc$里填上适当的运算符号。
$\frac{7}{15}+\frac{7}{12}+\frac{8}{15}-\frac{7}{12}=(\frac{7}{15}\bigcirc\frac{8}{15})\bigcirc(\frac{7}{12}-\frac{7}{12})$
$\frac{8}{25}+\frac{7}{13}+\frac{17}{25}+\frac{6}{13}=(\frac{8}{25}+\frac{17}{25})\bigcirc(\frac{7}{13}+\frac{6}{13})$
$\frac{7}{15}+\frac{7}{12}+\frac{8}{15}-\frac{7}{12}=(\frac{7}{15}\bigcirc\frac{8}{15})\bigcirc(\frac{7}{12}-\frac{7}{12})$
$\frac{8}{25}+\frac{7}{13}+\frac{17}{25}+\frac{6}{13}=(\frac{8}{25}+\frac{17}{25})\bigcirc(\frac{7}{13}+\frac{6}{13})$
答案:
+ + +
2. 在横线上填上适当的数。
$\frac{5}{7}+(\frac{1}{3}+\frac{2}{7})=(\frac{5}{7}+\_\_\_\_\_)+\_\_\_\_\_$
$11-\frac{7}{10}-\frac{3}{10}=\_\_\_\_\_-(\_\_\_\_\_+\frac{3}{10})$
$\frac{13}{16}-\frac{5}{12}+\frac{3}{16}-\frac{7}{12}=(\_\_\_\_\_+\_\_\_\_\_)-(\_\_\_\_\_+\_\_\_\_\_)$
$\frac{5}{7}+(\frac{1}{3}+\frac{2}{7})=(\frac{5}{7}+\_\_\_\_\_)+\_\_\_\_\_$
$11-\frac{7}{10}-\frac{3}{10}=\_\_\_\_\_-(\_\_\_\_\_+\frac{3}{10})$
$\frac{13}{16}-\frac{5}{12}+\frac{3}{16}-\frac{7}{12}=(\_\_\_\_\_+\_\_\_\_\_)-(\_\_\_\_\_+\_\_\_\_\_)$
答案:
$\frac{2}{7}$ $\frac{1}{3}$ 11 $\frac{7}{10}$
$\frac{13}{16}$ $\frac{3}{16}$ $\frac{5}{12}$ $\frac{7}{12}$
二、直接写出得数。
$\frac{3}{5}+\frac{2}{3}=$ $\frac{16}{25}+\frac{3}{10}=$ $\frac{4}{5}+\frac{3}{8}=$ $\frac{1}{2}-\frac{1}{8}=$
$\frac{1}{6}+\frac{1}{7}=$ $\frac{2}{5}-\frac{2}{9}=$ $\frac{1}{7}+\frac{6}{7}=$ $\frac{5}{12}-\frac{1}{4}=$
$\frac{1}{8}+\frac{2}{3}=$ $\frac{1}{3}-\frac{1}{8}=$ $\frac{5}{12}+\frac{1}{4}=$ $\frac{1}{24}+\frac{1}{3}=$
$\frac{1}{3}-\frac{1}{4}=$ $\frac{4}{9}-\frac{1}{4}=$ $\frac{1}{2}+\frac{1}{8}=$ $\frac{4}{15}+\frac{3}{20}=$
$\frac{5}{6}-\frac{3}{4}=$ $\frac{7}{8}-\frac{3}{4}=$ $\frac{5}{6}+\frac{1}{30}=$ $\frac{1}{4}+\frac{3}{8}=$
$\frac{3}{5}+\frac{2}{3}=$ $\frac{16}{25}+\frac{3}{10}=$ $\frac{4}{5}+\frac{3}{8}=$ $\frac{1}{2}-\frac{1}{8}=$
$\frac{1}{6}+\frac{1}{7}=$ $\frac{2}{5}-\frac{2}{9}=$ $\frac{1}{7}+\frac{6}{7}=$ $\frac{5}{12}-\frac{1}{4}=$
$\frac{1}{8}+\frac{2}{3}=$ $\frac{1}{3}-\frac{1}{8}=$ $\frac{5}{12}+\frac{1}{4}=$ $\frac{1}{24}+\frac{1}{3}=$
$\frac{1}{3}-\frac{1}{4}=$ $\frac{4}{9}-\frac{1}{4}=$ $\frac{1}{2}+\frac{1}{8}=$ $\frac{4}{15}+\frac{3}{20}=$
$\frac{5}{6}-\frac{3}{4}=$ $\frac{7}{8}-\frac{3}{4}=$ $\frac{5}{6}+\frac{1}{30}=$ $\frac{1}{4}+\frac{3}{8}=$
答案:
$\frac{19}{15}$ $\frac{47}{50}$ $\frac{47}{40}$ $\frac{3}{8}$
$\frac{13}{42}$ $\frac{8}{45}$ 1 $\frac{1}{6}$
$\frac{19}{24}$ $\frac{5}{24}$ $\frac{2}{3}$ $\frac{3}{8}$
$\frac{1}{12}$ $\frac{7}{36}$ $\frac{5}{8}$ $\frac{5}{12}$
$\frac{1}{12}$ $\frac{1}{8}$ $\frac{13}{15}$ $\frac{5}{8}$
三、计算下面各题,能简算的要简算。
$\frac{3}{5}+\frac{7}{13}+\frac{1}{5}$ $\frac{17}{18}-\frac{1}{3}-\frac{1}{3}$ $\frac{11}{12}-(\frac{1}{3}-\frac{1}{12})$
$\frac{1}{5}-(\frac{13}{15}-\frac{5}{6})$ $\frac{5}{6}-\frac{1}{4}+\frac{1}{3}$ $\frac{9}{7}-\frac{11}{15}-\frac{4}{15}$
$\frac{3}{5}+\frac{7}{13}+\frac{1}{5}$ $\frac{17}{18}-\frac{1}{3}-\frac{1}{3}$ $\frac{11}{12}-(\frac{1}{3}-\frac{1}{12})$
$\frac{1}{5}-(\frac{13}{15}-\frac{5}{6})$ $\frac{5}{6}-\frac{1}{4}+\frac{1}{3}$ $\frac{9}{7}-\frac{11}{15}-\frac{4}{15}$
答案:
$\frac{87}{65}$ $\frac{5}{18}$ $\frac{2}{3}$
$\frac{1}{6}$ $\frac{11}{12}$ $\frac{2}{7}$
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