《2025年口算训练三年级数学下册北师大版升级版》

$\frac{3}{5} - \frac{2}{5} =$ $\frac{5}{7} + \frac{1}{7} =$ $\frac{3}{8} - \frac{1}{8} =$
$\frac{3}{6} + \frac{2}{6} =$ $\frac{5}{9} + \frac{1}{9} =$ $\frac{6}{10} - \frac{4}{10} =$
$\frac{7}{10} + \frac{2}{10} =$ $\frac{2}{11} + \frac{4}{11} =$ $\frac{2}{11} + \frac{5}{11} =$

答案：

$1 - ( ) = \frac{1}{7}$ $\frac{4}{9} - ( ) = \frac{2}{9}$ $\frac{8}{15} + ( ) = 1$
$\frac{3}{6} + ( ) = \frac{5}{6}$ $\frac{3}{4} + ( ) = 1$ $\frac{2}{5} + ( ) = \frac{4}{5}$
$( ) + \frac{6}{9} = \frac{8}{9}$ $( ) + \frac{3}{8} = \frac{6}{8}$ $\frac{1}{11} + ( ) = \frac{3}{11}$
$( ) + \frac{2}{7} = \frac{5}{7}$ $( ) + \frac{4}{8} = 1$ $\frac{5}{9} + ( ) = \frac{8}{9}$

答案：

一张长方形纸，它的$\frac{1}{7}$涂蓝色，它的$\frac{3}{7}$涂红色，没有涂色的部分占这张纸的几分之几？

答案：