The one with a hole in it is a 50 yen piece from Japan. At today's exchange rate it's worth about $0.54. I can't see the kanji that comes before the 45 but the way they date coins is [kanji showing under which era/emperor the coin was minted] [ roman numerals of year after the start of that era/emperors reign][kanji for the word "year"], though they use kanji instead of numerals on some coins, I've got a 5 yen piece from showa 50(1970) that uses kanji instead, don't know how they decide that. The holed 50 yen piece was introduced in 1967 and the most recent era is less than 45 years old so I'd guess that's Showa 45 or 1970.