x----- is the whole number
a whole number is added to 25 , which means 25+x ;
a whole number is subtracted from 25 , which means 25 -x ;
Lets add them up to find the sum of resulting numbers :
(25+x) + (25-x) = 25 + x +25 - x = 50
Therefore, the sum of the resulting numbers is 50.
