Question

40!-39! sobre 41! não consigo.

Answer 1

$\frac{40!-39!}{41!} = \\ \\ = \frac{40.39!-39!}{41.40.39!} = \\ \\ = \frac{39!(40-1)}{41.40.39!} = \\ \\ = \frac{40-1}{41.40} = \\ \\ = \frac{39}{41.40} = \frac{39}{1640}$