How it works
Ben kept 50 pretend coins in a sock, but socks get holes and coins roll away. The Coin House is a made-up bank that keeps coins safe.
Three things guard every coin: a ledger, a vault and a promise. The ledger writes down whose coins are whose, so the coins can be mixed and never muddled.
The vault has a thick round door, a lock and a guard. The promise says Ben can have his coins back whenever he asks.
The vault does not hold every coin, because the house lends some out. Real banks follow strict rules and checks. Ask a grown-up how it works where you live.