b) 1/4 + 1/6 + 1/12 = 3/12 + 2/12 + 1/12 = 6/12 = 1/2 (Varianta 4)
c) 20/35 : (4/7) = 20/35 * 7/4 = 5/5 = 1 (Varianta 5)
d) (3/2 + 4/3 + 5/4)^2 * (2/4 - 1/4 - 1/6 - 1/12) = (18/12 + 16/12 + 15/12)^2 * (1/4 - 1/6 - 1/12) = (49/12)^2 * (3/12 - 2/12 - 1/12) = (49/12)^2 * 0 = 0 (Varianta 3)