\[\left| - 6\frac{3}{8} \right| - \left| - 1\frac{9}{16} \right| = 6\frac{3^{\backslash 2}}{8} - 1\frac{9}{16} =\]
\[= 6\frac{6}{16} - 1\frac{9}{16} = 5\frac{22}{16} - 1\frac{9}{16} =\]
\[= 4\frac{22 - 9}{16} = 4\frac{13}{16}\]