27 3/8-21 7/20 : (3 4/7 - 1 23/28) - (1 47/65 - 29/130)

27³/₈-21⁷/₂₀ : (3⁴/₇ - 1²³/₂₈) - (1⁴⁷/₆₅ - ²⁹/₁₃₀) = 13,675

3⁴/₇ - 1²³/₂₈ = ²⁵/₇ - ⁵¹/₂₈ = ²⁵ˣ⁴/₂₈ - ⁵¹/₂₈ = ¹⁰⁰/₂₈ - ⁵¹/₂₈ = ¹⁰⁰⁻⁵¹/₂₈ = ⁴⁹/₂₈ = ⁷/₄

21⁷/₂₀ : ⁷/₄ = 21⁷/₂₀ : ⁷/₄ = ⁴²⁷/₂₀ * ⁴/₇ = ⁴²⁷ˣ⁴/₂₀ₓ₇ = ⁶¹ˣ⁴/₂₀ = ⁶¹/₅ = 12,2

27³/₈ - 12,2 = 27,375 - 12,2 = 15,175

1⁴⁷/₆₅ - ²⁹/₁₃₀ = ¹¹²/₆₅ - ²⁹/₁₃₀ = ¹¹²ˣ²/₁₃₀ - ²⁹/₁₃₀ = ²²⁴/₁₃₀ - ²⁹/₁₃₀ = ²²⁴⁻²⁹/₁₃₀ = ¹⁹⁵/₁₃₀ = 1,5

15,175 - 1,5 = 13,675