If the two-digit integers F and N are positive and have the same digits, but in reverse order, which of the following CANNOT be the sum of F and N?	Choose the correct choice from the following
A) 181
B) 165
C) 121
D) 99
E) 44
Since the question asks for the answer that CANNOT be the sum of F and N, and the answers are numbers, we can use a combination of TESTing VALUES and TESTing THE ANSWERS to eliminate the possible values and find the answer to the question.   We're told that F and N are two-digit positive integers and have the SAME DIGITS but in REVERSE ORDER. We're asked which of the 5 answers CANNOT be the SUM of F and N.   Let's start with the 'easiest' answer first:   44. Can we get to 44 in the manner described?   Yes, if the numbers are 13 and 31.....13+31 = 44. Eliminate Answer E   Now let's work through the rest of the list....   Can we get to 99 in the manner described?   Yes, there are several ways to do it. For example, if the numbers are 18 and 81.....18+81 = 99. Eliminate Answer D   Can we get to 121 in the manner described?   Yes, there are several ways to do it. For example, if the numbers are 38 and 83.....38+83 = 121. Eliminate Answer C   Can we get to 165 in the manner described?   Yes, there are a couple of ways to do it. For example, if the numbers are 78 and 87.....78+87 = 165. Eliminate Answer B   There's only one answer left....   181
<result>A</result>
If the two-digit integers F and N are positive and have the same digits, but in reverse order, which of the following CANNOT be the sum of F and N?