\sqrt{\frac{49}{64} }-\sqrt \frac{25}{144} =\frac{7}{8} -\frac{5}{12} = \frac{21-10}{24} =\frac{11}{24} \\\\
\sqrt{\frac{81}{25} }-\sqrt \frac{9}{100} =\frac{9}{5} -\frac{3}{10} = \frac{18-3}{10} =\frac{15}{10} =\frac{5}{2} \\\\\\
