haha. Sir Bertrand Russel and Roger Penrose wrote entire books until the foundation for the number 1 was there! That by far exceeds the character limit here.
Firstly, it's absolutely necessary to convert that number to unary because everything gets confusing with any other numeral system.
1+1=11.
If you count the number of ones, you'll see that there are two of them to the right and to the left of the equals sign. So, since x=x and 1=1, we can conclude that the calculation is true.
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