The big ideaA bank keeps coins safe with a ledger, a vault and a promise.
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.
📒ledger🔒vault📜promise
The three guards of the Coin House.The ledger knows whose coins are whose.Of 100 coins in the Coin House.
Example 1: Reading the ledger
The ledger says Ben 50, Maya 30 and Ana 20.
50 + 30 + 20 = 100 coins in the Coin House.
The coins are mixed, but the ledger knows whose are whose.
Example 2: Taking coins out
Ben asks for 20 of his 50 coins.
The clerk checks the ledger and counts out 20.
50 − 20 = 30, so the ledger now says Ben, 30.
Example 3: The vault and the lending
Of 100 coins, 60 stay in the vault.
100 − 60 = 40 coins are lent to Baker Cy.
Baker Cy repays with a little extra, which helps the house keep its promise.
Example 4: Safe or not safe?
A thick vault door, a ledger, a guard and a signed promise keep coins safe.
A sock with a hole, coins left on the counter overnight and an open window do not.
Ask: does it guard the coins?
Words to know
bank
A place that keeps coins safe.
ledger
The book that writes down whose coins are whose.
vault
A strong room with a thick door, a lock and a guard.
promise
Ben can have his coins back whenever he asks.
lend
Let someone borrow coins, to be repaid with a little extra.
Watch out
Coins in a bank are mixed together. The ledger, not a box with a name on it, shows which are yours.
The vault does not hold every coin. Some are lent out.
A secret code written where anyone can see it is not safe.
The Coin House is made up. Ask a grown-up how a real bank keeps money safe where you live.
Try it
The ledger says Ben 50, Maya 30 and Ana 20. How many coins are there?
Ben takes out 20 of his 50 coins. What does the ledger say for Ben now?
Which one is not safe: a vault door, a sock with a hole, or a guard?
Of 100 coins, 60 are in the vault. How many are lent out?
Answers: 1. 100 coins · 2. 30 · 3. A sock with a hole · 4. 40 coins
Try at homeAsk a grown-up how their bank keeps their money safe, and what happens if they ask for it back.
For grown-upsAsk your child to tell you the three guards of the Coin House, then talk about how your own bank keeps money safe, at whatever level you are comfortable with. The Coin House is made up, and Tutorpip tracks money but never holds it.
Open these notes on screenScan the code, or go to tutorpip.com.