Decent explanation to it here. Welcome anyone on AF to challenge, but I think denominating the Put on yen in yen was nothing more than a trick – probably is dead obvious if you’re strong in currency. Was not to me.
Upshot: inversion of Put price/bid is not a normal step, but for sure the inverted values should be picked up.
You are asked to calculate exposure in currencies different than domestic as I recall domestic was CAD and as final step calculate net G/L in domestic currency units, CAD. Thus to get CAD/JPY and finally loss in CAD you have to simply reverse a put strike expressed as JPY/CAD to get strike in form of CAD/JPY. Another exposure in EUR was correctly expressed in EUR as base currency.
Currency is asset as any other asset. Try to think as exposure CAD/Bananas and you should calculate loss or gain in CAD not in bananas.