2,7x{3-18/19[0,5+0,(5)]}-13=
2,7x[3 - 18/19(5/10+5/9)] - 13 =
2,7x[3 - 18/19(45/90+50/90] - 13 =
2,7x(3 - 18/19 × 95/90) - 13 =
2,7x(3 - 1/1 × 5/5) - 13 =
2,7x(3 - 1) - 13 =
2,7x2 - 13 =
5,4 - 13 = -7,6
