Since 1 Australian Dollar is equal to 0.6652001221307424 US Dollars, we could say that n Australian Dollars are equal to 0.6652001221307424 times n US Dollars. In other words, we could use the following formula:
US Dollars = Australian Dollars x 0.6652001221307424
For example, let's say that we want to convert 2.0 Australian Dollars to US Dollars. Then, we just replace Australian Dollars in the abovementioned formula with 2.0:
US Dollars = 2.0 x 0.6652001221307424
That is, 2.0 Australian Dollars are equal to 1.3304002442614848 US Dollars.