The big ideaInterest is extra coins a bank garden adds for keeping your coins there.
How it works
A bank keeps coins safe. In the made-up Bank Garden, the garden adds a little extra to coins left there. That extra is called interest.
In this garden, interest was one new coin for every ten coins. One hundred coins are ten tens, so year one added 10 coins.
In year two the garden held 110 coins, which is eleven tens, so it added 11 coins. The new coins earn interest too.
This garden is made up, so the numbers are easy. Real banks use different numbers, and a grown-up can tell you more.
The interest the garden added.Interest, and what is not interest.
Example 1: Year one
Ana leaves 100 coins in the garden.
One new coin for every ten: 100 coins are 10 tens, so 10 new coins.
100 + 10 = 110 coins.
Example 2: Year two
The garden holds 110 coins, which is 11 tens.
Eleven tens bring 11 new coins.
110 + 11 = 121 coins.
Example 3: How much was interest?
Ana planted 100 coins and ended with 121.
121 − 100 = 21.
So 21 coins came from interest: 10 in year one and 11 in year two.
Example 4: A smaller garden
A garden holds 50 coins, which is 5 tens.
Five tens bring 5 new coins.
50 + 5 = 55 coins.
Words to know
bank
A place that keeps coins safe.
interest
The extra coins a bank garden adds for keeping your coins there.
Watch out
Interest is only the extra coins the garden adds, not the coins Ana planted herself.
A gift from Gran or a coin found on a path is not interest.
Coins taken out of the garden are not added. They are not interest.
Year two adds 11, not 10, because the new coins earn interest too.
Try it
Fifty coins go in the garden. How many new coins come in a year?
Ana has 110 coins. How many new coins does year two add?
Why did year two add more than year one?
Are the coins Ana planted interest?
Answers: 1. 5 · 2. 11 · 3. The new coins earned interest too · 4. No
Try at homeAsk a grown-up how interest works at a real bank, because this garden was made up.
For grown-upsThe Bank Garden is made up, and real banks use different numbers, so look at how a real bank explains interest together. The credits your child earns in the app are tracked by the app and never earn interest.
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