Ben visits the park every 2 days and goes to the library every 5 days. If Ben gets to do both of the

Ben visits the park every 2 days and goes to the library every 5 days. If Ben gets to do both of these today, how many days will pass before Ben gets to do them both on the same day again?

To find this, we want the least common multiple (LCM) of 2 and 5. We type LCM(2,5) into our search engine and we get:
10 days

We check our work:
2 days * 5 visits = 10 days
5 days * 2 visits = 10 days