1) 3-(¹/₆+²/₃) = 3 - ¹⁺⁴/₆ = 3 - ⁵/₆ = 2⁶/₆ - ⁵/₆ = 2¹/₆
2) 2 ²/₅-(¹/₄+⁷/₁₀) = 2 ²/₅- ⁵⁺¹⁴/₂₀ = 2 ²/₅- ¹⁹/₂₀ = ¹²/₅ - ¹⁹/₂₀ = ⁴⁸⁻¹⁹/₂₀= ²⁹/₂₀=1⁹/₂₀
3) 9-(1 ⁵/₈+³/₂₀) = 9- (¹³/₈+³/₂₀)=9-(⁶⁵⁺⁶/₄₀)= 9-⁷¹/₄₀=8⁴⁰/₄₀-1³¹/₄₀=7⁹/₄₀
4) 4⁵/₆-(2 ³/₈+⁷/₁₂)=²⁹/₆-(¹⁹/₈+⁷/₁₂)= ²⁹/₆ - ⁵⁷⁺¹⁴/₂₄= ²⁹/₆ - ⁷¹/₂₄=¹¹²⁻⁷¹/₂₄=⁴¹/₂₄=1¹⁷/₂₄