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$\frac{7}{8} - \frac{1}{4} + \frac{1}{8} =$ $\frac{1}{2} + 2 + \frac{1}{2} =$
$\frac{2}{3} + \frac{5}{6} - \frac{1}{6} =$ $\frac{1}{14} + \frac{5}{14} - \frac{3}{14} =$
$1 - \frac{7}{12} - \frac{5}{12} =$ $\frac{4}{9} + \frac{1}{3} + 1 =$
$\frac{5}{7} - \frac{1}{7} + \frac{2}{7} =$ $\frac{11}{12} - \frac{5}{12} + \frac{1}{12} =$
$1 - \frac{7}{15} + \frac{4}{15} =$ $\frac{1}{2} + \frac{7}{10} - \frac{1}{5} =$
$\frac{1}{2} - \frac{1}{3} + \frac{1}{4} =$ $\frac{4}{5} - \frac{3}{10} + \frac{1}{10} =$
$\frac{7}{8} - \frac{1}{2} - \frac{1}{8} =$ $1 - \frac{7}{10} + \frac{1}{5} =$
$\frac{5}{9} + \frac{4}{9} - \frac{3}{8} =$ $\frac{5}{8} - \frac{1}{6} + \frac{3}{8} =$
$1 - \frac{6}{13} + \frac{7}{13} =$ $\frac{2}{5} + \frac{1}{3} - \frac{1}{15} =$

连一连
$\frac{1}{2} - (\frac{1}{4} - \frac{1}{6})$ $\frac{1}{2} + \frac{1}{4} + \frac{1}{6}$
$\frac{1}{2} + (\frac{1}{4} - \frac{1}{6})$ $\frac{1}{2} - \frac{1}{4} - \frac{1}{6}$
$\frac{1}{2} + (\frac{1}{4} + \frac{1}{6})$ $\frac{1}{2} + \frac{1}{4} - \frac{1}{6}$
$\frac{1}{2} - (\frac{1}{4} + \frac{1}{6})$ $\frac{1}{2} - \frac{1}{4} + \frac{1}{6}$