Track / Stage 4 / 23 of 340 #283 of 1964

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

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A number or a short expression. Spacing, $ signs and \frac vs / are all fine.

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Official solution

19. 6

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.