For example, if option contract has condition: $AUDUSD = 0.8$ at the maturity date, and current exchange rate is $1 AUD = 0.75 USD$.
For this option, it could be considered a call option on $USD$, and put option on $AUD$ since $AUDUSD$ means that $AUD$ is sold 1 to buy $USD$ 0.8.
For the call option perspective, I get that strike price is $0.8$.
What I don't understand is the strike and spot price of the put option.
Why is it that spot for the put is 1, not 1.33( = 1/0.75), and strike is 0.9375(0.75/0.8), not 1.25( = 1/0.8) ?
Maybe I'm missing some basic concept about Fx or put options?
Thanks in advance.