7:22 オーストラリア人です you should have no problems exchanging coins, you can do it at a machine in any bank. Maybe you have to open a bank account though, just bring your passport. 問題あったら連絡してください
3:31 Hi from Australia! Those paper notes are more than their face value. They are very old. The $10 and the $1 is the design from maybe 30 years ago. If you go to a bank, the younger people working there won't recognise them, and no machines will accept them.
