The Turtles’ Slow and Steady Secret: Watch $100 Grow for Ten Years

Grandpa Explains Compounding

How $100 grows for ten years — the story behind the lesson in Investing with the Three Little Pigs

Do you remember when the Three Little Pigs visited the Turtles?

“Slow and steady is our plan!” said Mr. Turtle. And the Third Pig’s eyes grew wide when Mrs. Turtle explained the best part: the bank pays interest on your interest, too.

But what does that really look like? The Pigs wanted to see it for themselves. So on their next visit to the coast, Grandpa Pig sat them down at his kitchen table with a pencil and a piece of paper.

“Let’s pretend you invest one hundred dollars,” said Grandpa, “and it earns ten percent every year. We’ll use ten percent because it makes the math easy — watch what happens.”

“Ten percent of one hundred dollars is ten dollars,” said the First Pig. “So after one year, we’d have one hundred ten dollars.”

“Right!” said Grandpa. “Now here’s the secret the Turtles told you. In year two, you don’t earn interest on just your hundred dollars. You earn it on the whole one hundred ten.”

The Second Pig did the math. “Ten percent of one hundred ten dollars is… eleven dollars! We’d earn MORE in year two than in year one — without adding a single penny!”

“And in year three, you earn even more than that,” said Grandpa. “Your money earned money, and then THAT money earned money. It’s called compounding. Every year, the pile grows a little faster than the year before.”

The Third Pig grabbed the pencil and kept going, year after year. Here’s what he wrote down:

The Third Pig’s Ten-Year Table

$100 invested, earning 10% each year

Year	Interest Earned	Total
Start	—	$100.00
1	$10.00	$110.00
2	$11.00	$121.00
3	$12.10	$133.10
4	$13.31	$146.41
5	$14.64	$161.05
6	$16.11	$177.16
7	$17.72	$194.87
8	$19.49	$214.36
9	$21.44	$235.79
10	$23.58	$259.37

“Two hundred fifty-nine dollars!” cheered the Third Pig. “We more than DOUBLED our money — and we never lifted a hoof!”

“Now look closely at the table,” said Grandpa. “In year one, you earned ten dollars. In year ten, you earned almost twenty-four dollars. Same money, same ten percent — but the interest more than doubled. That’s your money doing the work for you.”

The First Pig noticed something else. “If the bank had only paid interest on our first hundred dollars every year, we’d have two hundred dollars after ten years. Compounding gave us fifty-nine dollars extra — for free!”

“That’s the Turtles’ secret,” Grandpa smiled. “Slow and steady doesn’t just win the race. It wins bigger the longer you stay in it. The three most important words in investing are: leave it alone.”

Try It Yourself

• Start your own table. Pick any amount — even $10 — and work out ten years of growth with your child, one row at a time. Watching the interest column grow is the whole lesson.

• Play “double or wait.” Ask your child: would you rather have $200 today or $100 invested for ten years? Then show them year 15 ($417.72) and year 20 ($672.75). Patience changes the answer.

• Find the bend. Have your child draw the totals as a picture or graph. Compounding starts as a straight line and slowly bends upward — that bend is the magic.

A Note for Parents

We use 10% because it keeps the math kid-friendly — and it’s close to the long-run average return of the U.S. stock market before inflation. Real investments don’t grow in a smooth line: savings accounts pay much less, and stocks bounce up and down from year to year. The lesson to reinforce isn’t the exact number — it’s that time in the market matters more than the amount you start with. This is an educational example, not investment advice.

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From the parent’s guide in Investing with the Three Little Pigs • pigsandbricks.com