What is the sum of X+XX+XXX+XXXX?
Last Updated: 22.06.2025 10:23

However, X +X^2 +X^3 + X^4 is a valid algebraic answer,
*Note that the abbreviation XL (for XXXX) appeared quite late in the Roman period, and never found universal favour
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)
Pacific sediment cores unlock millions of years of climate history - Earth.com
What is the sum of X+XX+XXX+XXXX?
1234X
It’s a matter of interpretation.
Social Security's 2026 COLA Has an Unpleasant Surprise in Store for Retirees - The Motley Fool
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
11010X
and for binary would be