《2025年阳光同学暑假衔接五升六年级数学北师大版》

例1 用简便方法计算：$\frac {5}{8}-\frac {1}{5}+\frac {3}{8}-\frac {4}{5}$。

答案： $\frac {5}{8}-\frac {1}{5}+\frac {3}{8}-\frac {4}{5}$
$=(\frac {5}{8}+\frac {3}{8})-(\frac {1}{5}+\frac {4}{5})$
$=1-1$
$=0$

1. 用简便方法计算。
$\frac {5}{7}-\frac {1}{3}+\frac {2}{7}-\frac {2}{3}$ $\frac {7}{9}-\frac {3}{11}-\frac {8}{11}+\frac {2}{9}$ $\frac {2}{9}+(\frac {7}{12}+\frac {7}{9})$
$\frac {5}{9}-(\frac {2}{5}-\frac {1}{9})$ $\frac {1}{3}+\frac {1}{4}-\frac {1}{3}+\frac {1}{4}$ $\frac {5}{7}-\frac {1}{12}-\frac {5}{6}+\frac {2}{7}$
$10-\frac {3}{8}-\frac {5}{8}$ $2.75-\frac {12}{25}+2.25-\frac {13}{25}$ $\frac {4}{9}+\frac {5}{12}+\frac {5}{9}+\frac {19}{12}$

答案： 0 0 $1\frac {7}{12}$ $\frac {4}{15}$ $\frac {1}{2}$ $\frac {1}{12}$ 9 4 3