What is the sum of X+XX+XXX+XXXX?
10.06.2025 00:20

Given the use of upper case, I personally would initially assume Roman numerals*, so the answer would be C (100 in present-day decimal notation)
However, X +X^2 +X^3 + X^4 is a valid algebraic answer,
as would be assuming that these are representations of conventional numbers, in which case the answer for number bases of five or more would be
What can help me fall asleep at night?
What is the sum of X+XX+XXX+XXXX?
It’s a matter of interpretation.
1234X
Why do some of those who believe in a god refuse to consider the possibility they could be wrong?
11010X
*Note that the abbreviation XL (for XXXX) appeared quite late in the Roman period, and never found universal favour
and for binary would be