MathDB

4

Part of 2019 Girls in Mathematics Tournament

Problems(1)

cute numbers less than 2019, n is cute when m! ends in n zeros

Source: 1st Girls in Mathematics Tournament 2019 p4 (Brazil) / Torneio Meninas na Matematica (TM^2 )

5/25/2020
A positive integer nn is called cute when there is a positive integer mm such that m!m! ends in exactly nn zeros. a) Determine if 20192019 is cute. b) How many positive integers less than 20192019 are cute?
factorialnumber theorycombinatorics