Question 18
For any positive integer n, we have $n!=1\times2\times3\times\cdots\times n$. If the last two digits of $1!+2!+3!+4!+\cdots+2025!$ is $\overline{ab}$, what is the value of $\overline{ab}$?
IMSO Maths · IMSO 2025 Mathematics — International Short Answer