Consider the following two strings of digits: $11001010100101011$ and $110100011000100$. First consider them to be in base $10$ and sum them to get $n$. Then consider them to be in binary, sum them, write the answer in binary, then interpret the digits of the sum as if they were in base $10$ to get $m$. What is $n-m$?
This is just a computation problem: n = 11201201201221012 and m = 835718428, so n - m = 11201200365502584.