What is the sum of X+XX+XXX+XXXX?
Last Updated: 23.06.2025 04:43

1234X
*Note that the abbreviation XL (for XXXX) appeared quite late in the Roman period, and never found universal favour
It’s a matter of interpretation.
Where the Stock Market Stands Now After a Wild Start to the Year - Bloomberg.com
However, X +X^2 +X^3 + X^4 is a valid algebraic answer,
What is the sum of X+XX+XXX+XXXX?
and for binary would be
A runway under construction at Newark's beleaguered airport reopens early - NPR
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)
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 Club World Cup is finally up and running — and soccer may never be the same - AP News