Find three consecutive even integers such that the sum of the smallest to the largest 36

If they were all the same integer, then each one would be
1/3 of 36, and you would have

                                           12  +  12  +  12  =  36 .

But you don't want them to all be the same number.  You
want them to be three consecutive even numbers.

Fine !  Take 2 away from the first 12, and glue it onto the last 12 .
Their sum doesn't change, but now you have

                                             10  +  12  +  14  =  36 .