1+1=2 has a correct interpretation in any base 3 and higher. How we know that it wasn't to be calculated in binary is that the digit 2 occurs. We have to have

1+1=2 has a correct interpretation in any base 3 and higher. How we know that it wasn't to be calculated in binary is that the digit 2 occurs. We have to have a reason to suspect that it was intended to be binary, otherwise we are inventing an inconsistency that isn't there in order to find a false or not-well-formed interpretation.