If you have $500,000 and the yen exchange rate is .007, you would have
500,000/.007 = 71,428,571.43 yen
Then, if the exchange rate to Canadian dollars is 118 then you would have
71428571.43/118 = 605,326.88 dollars
Then if the exchange rate back to US dollars is .821, you would end up with
605,326.88 / .821 = $737,304.36