(2 ⁷/₁₂ + 1,75) : 13 + 2,5 : 3 ³/₄) = 13/45
1) 2 ⁷/₁₂ + 1,75 = 31/12 + 175/100 = 31/12 + 7/4 = 31 + 7*3 = 52/12 = 13/3
12
2) 13/3 : 13 = 1/3
3) 1/3 + 2,5 = 1/3 + 25/10 = 1/3 + 5/2 = 1*2 + 5*3 = 17/6
6
4) 17/6 : 3 ³/₄ = 17/6 : 15/4 = 17 * 4 = 34/45
6 * 15