7 ⁵/₁₂ + 4 ³/₈ = 7 ¹⁰/₂₄ + 4 ⁹/₂₄ = (7+4) + ⁽¹⁰⁺⁹⁾/₂₄ = 11 ¹⁹/₂₄
3 ¹¹/₂₀ + 2 ¹⁹/₃₀ = 3 ³³/₆₀ + 2 ³⁸/₆₀ = (3+2) + ⁽³³⁺³⁸⁾/₆₀ = 5+ ⁷¹/₆₀ =
= 5 + 1 ¹¹/₆₀ = 6 ¹¹/₆₀
9 ⁵/₆ - 2 ³/₄ = 9 ¹⁰/₁₂ - 2 ⁹/₁₂ = (9-2) + ⁽¹⁰⁻⁹⁾/₁₂ = 7 ¹/₁₂
3 ³/₁₀ - 1 ⁷/₁₅ = 3 ⁹/₃₀ - 1 ¹⁴/₃₀ = ⁹⁹/₃₀ - ⁴⁴/₃₀ = ⁵⁵/₃₀ = ¹¹/₆ = 1 ⁵/₆