Track / Stage 4 / 31 of 340 #291 of 1964

Problem 291

AMC 12 late, AIME early

Number theory Difficulty 4.6 Find the answer

What is the remainder when $(0!+1!+2!+\cdots+2011!)^{2}$ is divided by 10 ?

Your answer

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Official solution

19. 6

Source: NuminaMath-1.5, licensed Apache-2.0. Statement reproduced verbatim; metadata (topic, difficulty, ordering) added by this project.