Решение:

a) $$ \frac{0.4^2}{0.4^2 + 0.1} = \frac{0.16}{0.16 + 0.1} = \frac{0.16}{0.26} = \frac{16}{26} = \frac{8}{13} $$.

б) $$ \frac{0.5^2}{0.6^2 + 0.1} = \frac{0.25}{0.36 + 0.1} = \frac{0.25}{0.46} = \frac{25}{46} $$.

в) $$ \frac{1.22 - 1.82}{1.5 - 1.5} = \frac{-0.6}{0} $$. Деление на ноль не определено.

г) $$ \frac{6 - \frac{1 + 2 \cdot 0.25}{46}}{1 + 2.2 \cdot 10} = \frac{6 - \frac{1 + 0.5}{46}}{1 + 22} = \frac{6 - \frac{1.5}{46}}{23} = \frac{6 - \frac{3}{92}}{23} = \frac{\frac{552 - 3}{92}}{23} = \frac{\frac{549}{92}}{23} = \frac{549}{92 \cdot 23} = \frac{549}{2116} $$.