In the following, find the digits represented by the letters:
1 A A
+ 1 A A–––––––––
2 A A–––––––
In the given problem, the addition of A with A itself gives a number whose ones digit is A again. This happens only when A=0. In the next step, the same will be done that is:
A+A=A⇒0+0=0
In the last step, it is given that 1+1=2 and therefore, the required sum with A=0 is 100+100=200