Вычислите: а) 1/16 + (3/16 + 1/4); б) 1/12 + 1/18 + 5/18 + 3/12; в) 2/5 + 3/4 − 23/20.

1. \(\frac{1}{16}+\left(\frac{3}{16}+\frac{1}{4}\right)=\frac{1}{16}+\frac{3}{16}+\frac{4}{16}=\frac{8}{16}=\frac{1}{2}\).
2. \(\frac{1}{12}+\frac{1}{18}+\frac{5}{18}+\frac{3}{12}=\frac{4}{12}+\frac{6}{18}=\frac{1}{3}+\frac{1}{3}=\frac{2}{3}\).
3. \(\frac{2}{5}+\frac{3}{4}-\frac{23}{20}=\frac{8}{20}+\frac{15}{20}-\frac{23}{20}=\frac{0}{20}=0\).

Ответ: а) \(\frac{1}{2}\); б) \(\frac{2}{3}\); в) 0.