The big ideaA small amount saved every month adds up, and growth helps more as the years pass.
How it works
Kai drops ten pretend coins into the garden every month. Twelve months make 120 coins in a year.
On New Year's Day the garden counts the coins already inside, then adds one new coin for every ten.
In year one the garden is empty at New Year, so nothing grows yet. Later, growth builds on growth.
The first coins work the longest. Little by little, the garden does more work than Kai.
Who did the work?One year in the garden.
Example 1: A year of saving
Kai saves 10 coins a month.
12 months of 10 coins is 12 × 10 = 120.
So Kai holds 120 coins at the end of year one.
Example 2: Year two
On New Year's Day the garden holds 120 coins.
120 holds 12 tens, so it adds 12 new coins.
With 12 more months of pouches, the garden holds 252.
Example 3: Ten years
Kai put in 10 × 120 = 1200 coins.
The garden holds 1907.
Growth added 1907 − 1200 = 707 coins.
Example 4: Year nine
The garden adds 136 coins.
Kai saves 120 in a year.
136 − 120 = 16, so the garden added more than Kai saved.
Words to know
pouch
A month's ten coins, dropped in the garden.
growth
The new coins the garden adds on New Year's Day.
steady
A little, again and again.
Watch out
A garden that starts empty has nothing to grow in year one.
Growth is not the same every year. It gets bigger as the garden does.
Coins saved in the last year have had no time to grow.
This garden is made up. Real ones pay differently, and nothing is promised.
Try it
Kai saves 10 coins a month. How many in 12 months?
After 10 years Kai put in 1200 and the garden holds 1907. How much did growth add?
Which of Kai's coins grow for the most years?
In year nine the garden adds 136 and Kai saves 120. How much more is the garden's?
Answers: 1. 120 · 2. 707 · 3. The ones saved in year one · 4. 16
Try at homeWith a grown-up, pick something small you do steadily, like pages read or steps walked. Write it down each day, and add it up after a month to see how it grows.
For grown-upsPick one small habit together, like pages read or steps walked, and count it for a month. This is a made-up garden: talk about how a small steady thing adds up, not about any real account.
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