Divide by the amount of consecutive numbers (4 in this instance)
It will be within a small range of those numbers
ex. The sum of 3 consecutive even integers is 24.
24/3 =8
Now guess and check
4+6+8=18 that's not 24 so don't add 4 instead on the other side of 8 put 10
6+8+10=24
Do roughly the same thing