What is the sum of X+XX+XXX+XXXX?
Last Updated: 29.06.2025 07:49

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)
*Note that the abbreviation XL (for XXXX) appeared quite late in the Roman period, and never found universal favour
11010X
‘How To Train Your Dragon’ Flying In With $200M+ Worldwide Bow – International Box Office - Deadline
However, X +X^2 +X^3 + X^4 is a valid algebraic answer,
It’s a matter of interpretation.
What is the sum of X+XX+XXX+XXXX?
Tesla just lost the head of its robotics division - The Verge
1234X
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
and for binary would be