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