8) 9/12 + 16/20 − 9/10 и 3/6 − 2/8 + 6/12

\(\frac{9}{12}+\frac{16}{20}-\frac{9}{10}=\frac{3}{4}+\frac{4}{5}-\frac{9}{10}=\frac{15+16-18}{20}=\frac{13}{20}\).

\(\frac{3}{6}-\frac{2}{8}+\frac{6}{12}=\frac{1}{2}-\frac{1}{4}+\frac{1}{2}=\frac{3}{4}\).

\(\frac{13}{20}<\frac{3}{4}\), поэтому \(\frac{9}{12}+\frac{16}{20}-\frac{9}{10}<\frac{3}{6}-\frac{2}{8}+\frac{6}{12}\).