What is the sum of X+XX+XXX+XXXX?
Last Updated: 02.07.2025 18:04

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.
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
The Low Testosterone Symptoms to Look Out For—And How to Handle Them - GQ
*Note that the abbreviation XL (for XXXX) appeared quite late in the Roman period, and never found universal favour
and for binary would be
What is the sum of X+XX+XXX+XXXX?
N.J. doctors are using a party drug to send patients to ‘another planet.’ Yes, it’s legal. - NJ.com
11010X
However, X +X^2 +X^3 + X^4 is a valid algebraic answer,
1234X