What is the sum of X+XX+XXX+XXXX?
12.06.2025 03:38
11010X
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)
It’s a matter of interpretation.
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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 is the sum of X+XX+XXX+XXXX?
and for binary would be
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*Note that the abbreviation XL (for XXXX) appeared quite late in the Roman period, and never found universal favour
However, X +X^2 +X^3 + X^4 is a valid algebraic answer,
1234X