Given that the numbers are consecutive:
let the first number be x, the second number will be x+1, the third number be x+2
thus the sum of the numbers will be:
x+(x+1)+(x+2)=-381
3x+3=-381
3x=-381-3
3x=-384
x=-128
thus the first number is -128, the second number is -127 and the third number is -126