(0,4 - 11/15) * 1 2/7 - (7/18 - 0,5) : 1 1/6 = -1/3
1) 0,4 - 11/15 = 4/10 - 11/15 = 12/30 - 22/30 = -10/30 = -1/3
2) -1/3 * 1 2/7 = -1/3 * 9/7 = -9/21 = -3/7
3) 7/18 -0,5 = 7/18 - 5/10 = 7/18 - 1/2 = 7/18 - 9/18 = -2/18 = -1/9
4) -1/9 : 1 1/6 = -1/9 : 7/6 = -1/9 * 6/7 = -2/21
5) -3/7 - (-2/21) = -3/7 + 2/21 = -9/21 + 2/21 = -7/21 = -1/3