AUD/USD vs. AUD:USD

how do you know which goes on the bottom?

AUD:USD = USD/AUD

This confused me a little bit too when I started studying … I think of the ccy’s in terms of A and B. A is domestic, B is foreign. Presentation for direct quotes of ccy A: 1) ccy A per unit of ccy B. 2) A/B 3) B:A

Very helpful. Thank you.

just know that AUD:USD is the same as USD/AUD

when I see AUD:USD it reads “USD per AUD” which is the same as USD/AUD I start the sentence with whatever currency is after the " : " AUD:USDollars per AUD hope it makes sense.