(³⁾17/24 + ²⁾5/36) - (³⁾5/60 - ¹⁰⁾1/18) =
= (51 + 10)/72 - (15 - 10)/180
= 61/72 - 5/180
= 61/72 - ²⁾1/36
= (61 - 2)/72
= 59/72
(4 7/9 - 1 1/2) - (³⁾15/16 - ²⁾1/24) =
= (²⁾43/9 - ⁹⁾3/2) - (45 - 3)/48
= (86 - 27)/18 - 42/48
= ⁴⁾59/18 - ⁹⁾7/8
= (236 - 63)/72
= 173/72
