б) 0,25 - (-2 1/6)

1. Convert decimal and mixed number to fractions: 0.25 = 1/4, -2 1/6 = -13/6.
2. Rewrite the expression: 1/4 - (-13/6) = 1/4 + 13/6.
3. Find a common denominator (12) and add: (3 + 26) / 12 = 29/12.