SURFING:

IDIOM: get the hang of something?

MEANING 1 & 2: to understand something
SENTENCE 1: You're getting better at surfing. You're get the hang of it.
SENTENCE 2: Are you getting get the hang of that new business?

DERIVATION: The terms "hang ten and hang five are surfing terms referring to the number of toes used to grip the side of a surfboard. The use of many of the "hang" terms could have derived from these surfing terms.