1) |1,5-2,3|-4 = |-0,8|-4 = 0,8-4 = -3,2
2) |3*(-1,2)+1 4/15|+2/3 = |-3,6+1 4/15|+2/3 = |-3 3/5+1 4/15|+2/3 = |-18/5+19/15|+2/3 = |-54/15+19/15|+10/15 = |-35/15|+6/15 = 35/15+10/15 = 45/15 = 3
3) 11+|3/8*(-4/9)-5/6| = 11+|-3/18-15/18| = 11+|-18/18| = 11+|-1| = 11+1 = 12
4) 8/9+|1/12*(-4)-7/9| = 8/9+|-1/3-7/9| = 8/9+|-3/9-7/9| = 8/9+|-10/9| = 8/9+10/9 = 18/9 = 2