1+1/2:1/3*6=1+1/6*6=1+1=2
2/5 * 2 1/2 - 1 1/3 * 3/4 = 2/5 * 5/4 - 4/3*3/4 = 1/2 - 1 = - 1/2
(2 5/6 - 1 2/3) : 7 + 5/6 = (2 5/6 - 1 4/6) : 7 + 5/6 = 1 1/6 : 7 + 5/6 = 7/6*1/7+5/6=
1/6+5/6=1
1 - 3,5 * 2 : 0,2= 1 - 7 : 0,2 = 1 - 35 = -34
