5th Grade — Money & Business

Compound interest, the cost of borrowing, and a written business plan.

Ages 10–11

The one idea

Money you leave alone grows on its own — and money you borrow shrinks the same way.

Lesson 1 of 6

💼 Earn

Trading time vs building something

Mowing a lawn pays once. Writing instructions that let ten people mow lawns can pay over and over. The first is a job; the second is an asset. Most people only ever build the first kind.

Two summers of work, measured over three years.

Ines — babysitting, year 1$840
Ines — babysitting, year 2$840
Same work, same money, every year
Rafa — the website, year 1$0
A whole summer for nothing
Rafa — the website, year 2$600
Earned while he was at football camp

Ines is well ahead after two years. The reason to look at Rafa's bars anyway is the direction they are pointing.

Lesson 1 of 6 · A story

The two summers

Ines spent her summer babysitting at $12 an hour and made $840. Her brother Rafa spent his summer building a small website that listed every dog-friendly café in their town, and made $0. The next summer Ines babysat again and made $840. Rafa's site had a few local ads on it by then and made $600 while he was at football camp.

Who had the better summer, and when does that answer change?

Ines, clearly, in year one. The answer flips somewhere in year two — not because Rafa is smarter, but because his summer kept working after it ended and hers didn't.

Lesson 1 of 6 · Try it

The usual mistake

Hearing this and concluding hourly work is a mistake. Rafa ate for a year on nothing, which only worked because he was twelve and living at home.

The fix

Do both. Trade time for the money you need now, and spend a slice of that time building something that keeps paying.

Do this

List three ways they could earn $50. Mark which ones stop paying the moment they stop working.

Say this

"If you got sick for a month, which of these still pays you? That's the difference that matters."

Lesson 2 of 6

🏦 Save

Compound interest

Interest earns interest. $100 at 10% becomes $110 — and next year you earn 10% on $110, not $100. It looks tiny for years, then it bends sharply upward. That bend is why starting early beats starting big.

$1,000 left completely alone at 7% a year.

Start$1,000
After 10 years$1,967
Nearly doubled
After 20 years$3,870
Doubled again
After 30 years$7,612
After 40 years$14,974
Same $1,000. Nothing was ever added.

The last ten years added more than the first thirty. That is why starting early beats saving hard.

Lesson 2 of 6 · A story

The chessboard problem

There's an old story about an inventor who asked a king for one grain of rice on the first square of a chessboard, two on the second, four on the third, and so on. The king agreed instantly because it sounded like nothing. By square twenty-one it was over a million grains. By the last square, more rice than has ever existed.

Why did the king get it so wrong?

Because human beings are built to expect things to add and this thing multiplied. Doubling looks like nothing for a long time and then it looks like everything, and there is no warning in between.

Lesson 2 of 6 · Try it

The usual mistake

Judging compounding by the first few years. Year one of a 7% return on $1,000 is $70, which is genuinely boring.

The fix

Always look at the whole curve. The boring years are not a sign it isn't working — they are how it works.

Do this

Work out $100 at 10% for ten years, one year at a time, on paper. Do not use a shortcut — the point is watching it accelerate.

Say this

"Year one you made $10. Work out year ten. Why is that number so much bigger for the same 10%?"

Lesson 3 of 6

🛒 Spend

Price is not the same as value

A $60 pair of boots that lasts three winters is cheaper than a $25 pair that dies each year. Cost per use is the honest number, and it often points the opposite way to the price tag.

Two ways to keep your feet warm for seven winters.

$25 boots, replaced every year

$175

Seven pairs at $25. Cold feet in most of them.

✓ Better deal

$80 boots, lasted 7 winters

$80

Under $12 a winter, and warm the whole time.

Cost per year is the number that compares them. The sticker price cannot, because it is measuring different things.

Lesson 3 of 6 · A story

The $80 boots and the $25 boots

Dara's mum bought $25 winter boots three winters running because $80 felt ridiculous. In the fourth winter she bought the $80 pair. Dara worked out that the cheap route had cost $75 for three cold-footed winters, and the expensive pair was still going four years later.

Which pair was actually expensive?

The cheap ones — $75 for three winters against $80 for seven. Price is what you hand over. Value is what you get divided by how long it lasts.

Lesson 3 of 6 · Try it

The usual mistake

Flipping this into "buy the expensive one". Plenty of expensive things are just expensive, and this reasoning is exactly what a salesperson wants you to do.

The fix

Work out cost per year, per wear, or per use. That number compares things the sticker price cannot.

Do this

Take one thing they own and divide what it cost by the number of times they've used it.

Say this

"You've worn those about 200 times. So what did each wear actually cost you?"

Lesson 4 of 6

💝 Give

Giving a percentage, not a leftover

If you give a fixed percentage, your giving grows automatically as you earn more, and you never have to renegotiate with yourself. People who pick a percentage early tend to keep it for life.

Malik's giving over four months, both ways.

Good month — 10% of $60$6
Quiet month — 10% of $22$2.2
Still gave. Barely noticed.
Bad month — 10% of $8$0.8
80¢ — and the habit survived
Bad month — the old fixed $5$5
Unaffordable, so he skipped it and then stopped

A percentage bends. A fixed amount breaks — and it breaks in the month you were least able to start again.

Lesson 4 of 6 · A story

The percentage that survived a bad month

Malik gave $5 a month to a food bank. In a month where he earned almost nothing, $5 was a lot and he skipped it, and then he skipped the next one too. When he switched to giving 10% of whatever came in, the bad month cost him 80¢ and he never stopped again.

Why did a percentage survive when a fixed amount didn't?

Because a percentage shrinks with you. A fixed amount becomes impossible in a bad month, and the habit breaks at exactly the moment it was hardest to keep.

Lesson 4 of 6 · Try it

The usual mistake

Fixed-dollar giving. It is generous in a good month and unaffordable in a bad one, and one skipped month usually ends it for good.

The fix

Pick a percentage and keep it through both. 10% of a bad month is small, and the streak stays alive.

Do this

Pick a percentage — most people land between 5% and 10% — and apply it to every dollar for three months.

Say this

"Pick the number now, while the amounts are small. Deciding is much harder when the sums get big."

Lesson 5 of 6

📈 Grow

Borrowing runs the same machine backwards

Compounding doesn't care which direction it points. Borrow $100 at 20% and you owe $120 — then interest starts running on the $120. This is exactly why unpaid debt gets away from people.

$500 borrowed at 20%, paying only the interest each year.

Borrowed once$500
Interest paid over 5 years$500
Still owed at the end$500

Five years, $500 handed over, and the debt is exactly the size it was on day one.

Lesson 5 of 6 · A story

The machine, running backwards

Ola had learnt that compound interest turns small money into big money if you wait. Then her uncle showed her his old credit card statement. He had borrowed $500 once, years ago, paid only the interest each month, and by then had handed the bank more than $500 — while still owing the entire original $500.

What did the bank sell him?

Nothing. He paid over $500 for the use of $500 and kept the debt. Interest works exactly as hard against you as it works for you, and usually at a much higher rate.

Lesson 5 of 6 · Try it

The usual mistake

Treating saving and borrowing as separate topics. They are the same machine with the arrow pointing the other way.

The fix

Whenever a rate comes up, ask which side of it you are standing on. 20% is a thrilling number to earn and a brutal one to pay.

Do this

Run the same ten-year table as before, but for a $100 debt at 20%. Compare the two curves side by side.

Say this

"Same machine, opposite direction. Would you rather own it or owe it?"

Lesson 6 of 6

🧠 Mindset

Write the plan down

An idea in your head feels finished. Written down, the gaps show up immediately — who buys it, what it costs, what could go wrong. Writing it is the cheapest way to find out an idea doesn't work.

Sam's one page, in the order it has to be filled in.

What it costs me per unit$1.40
What I planned to charge$1.00
Profit per sale, as planned−$0.40

He would have lost 40¢ on every single sale, and the busier the stall got the worse it would have been.

Lesson 6 of 6 · A story

One page, and the question it caught

Sam had a good idea for a school-fair stall and his teacher made him write it on one page: what it is, who buys it, what it costs him, what he charges. Filling in "what it costs him" took eleven minutes and revealed that his ingredients cost more than he had planned to charge. He changed the price before he had spent a cent.

What did the page actually do?

It forced him to answer four questions in a fixed order, and one of them was fatal. An idea in your head is allowed to skip the fatal question. A page is not.

Lesson 6 of 6 · Try it

The usual mistake

"I'll work it out as I go." You will — after you have bought the ingredients.

The fix

One page, four boxes, before any money is spent. If a box can't be filled in, that box is the whole problem.

Do this

One page, five headings: what it is, who buys it, what it costs to make, what you'll charge, what could go wrong.

Say this

"Fill in every heading. The one you can't answer is the one that would have sunk it."

🤔 What would you do? · 1 of 3

There is no silly option here — every one is something a reasonable person would pick.

You've saved $1,000. You could put it somewhere paying 7% and leave it for 30 years, or spend it now on something you'd enjoy.

🫙 Allowance calculator

The Four Jars

Move the sliders and watch what each jar becomes. Only the Grow jar is invested, so only Grow compounds — that is the whole reason the numbers separate.

Money in each week

Save25% · $2.50/week

$130 a year → $1,300 after 10 years

Spend30% · $3.00/week

$156 a year → $1,560 after 10 years

Give10% · $1.00/week

$52 a year → $520 after 10 years

Growinvested · 7%35% · $3.50/week

$182 a year → $2,691 after 10 years

Look ahead:

You put in

$5,200

You end up with

$6,071

Grew on its own

+$871

That extra $871 is money nobody worked for. It came from the Grow jar earning 7% a year on a balance that keeps getting bigger.

For parents: About $10 a week. At this level the grow jar can fund a genuine venture, which is the point of raising it.

The 7% is a rough long-run stock market average used for illustration. Real returns vary, some years are negative, and nothing here is investment advice.

📖 The words they need this year

Compound interest: Interest that earns interest of its own.; Like: $100 at 10% is $110, then $121, then $133.
Principal: The starting amount, before any interest.; Like: The original $100 you deposited.
Debt: Money you owe someone else.; Like: The $50 you borrowed for stock.
Asset: Something you own that keeps paying you.; Like: A vending machine, or a book that keeps selling.
Cost per use: The price divided by how many times you use it.; Like: $60 boots worn 200 times is 30¢ a wear.
Business plan: A written page saying how the idea makes money.; Like: What it is, who buys it, what it costs, what you charge.

📜 This actually happened

Benjamin Franklin's 200-year experiment

When Benjamin Franklin died in 1790 he left about £1,000 — roughly $4,400 at the time — to each of Boston and Philadelphia, with instructions that the money be lent out to young tradesmen and not fully distributed for two hundred years. He wanted to prove a point about patience. By 1990, when the trusts finally paid out, Boston's share had grown to around $5 million and Philadelphia's to about $2.3 million.

He never added a penny after 1790. The only ingredient was time, and he was willing to be dead for most of it.

This week's mission

The Compounding Table

They watch the curve bend with their own arithmetic, which no explanation can substitute for.

⏱️ 40 minutesPaperA calculator

1Draw three columns: YEAR / START / END.
2Start with $100 at 10%. Fill in ten rows, one year at a time — no shortcuts.
3On the same sheet, run a second table: $100 borrowed at 20%, ten years.
4Plot both as a rough line graph on one set of axes.
5Write one sentence about what happens to the two lines after year six.

🚀 Starter business

The One-Page Business

"Here's the plan, in writing, before I spend a cent."

What it costs to start

$0 to plan; set your own cap before you start

What to charge

Work backwards: pick the profit you want per sale, add your cost per unit, and that's your price.

1Write the one-pager: what it is, who buys it, cost to make, price, what could go wrong.
2Show it to one adult who will actually poke holes in it.
3Fix the weakest section. There is always a weakest section.
4Set a hard spending cap before you buy anything.
5Run it for two weeks, then compare real numbers against the plan's numbers.

The business lesson underneath

The gap between planned numbers and real numbers is where all the learning is. Plans are wrong; planning still pays.

Back

Ready?

5th Grade — Money & Business

Compound interest, the cost of borrowing, and a written business plan.

Full screen — no distractions

For grown-ups: 5th Grade money

Ten and eleven year olds can do the compounding arithmetic themselves, which matters: seeing the curve bend is far more convincing than being told it does.

Four questions to ask this week

No printing, no materials, no lesson. Ask one at dinner and let the answer go wherever it goes — most of what children learn about money they overhear.

1"What's something you could build once that would still be useful next year?"
2"Cost per year — how would you work it out for this?" Pick something expensive in the house.
3"Is 20% a good number or a terrible number?" Answer: it depends entirely which side of it you're standing on.
4"What would your one page say?" Make them fill in all four boxes out loud, especially the cost one.

Three habits that matter at this age

The money lessons only stick if these are running underneath them.

Show them the curve, don't describe it

Compounding is unconvincing as a sentence and undeniable as a graph they drew themselves. Make them plot it.

Write plans before spending money

A one-page plan takes twenty minutes and routinely saves the whole budget by exposing the missing customer.

Compare plan to reality afterwards

The review is worth more than the plan. Where were you wrong, and by how much? That calibration is a rare adult skill.

By the end of 5th Grade

Tick these off through the year. If one is still open in June, that's the lesson to go back to.

Calculates compound interest year by year without a formula
Explains why early saving beats larger later saving
Uses cost per use rather than price to compare purchases
Explains how compounding makes unpaid debt grow
Writes a one-page business plan covering all five headings
Gives a fixed percentage of everything they receive

Want the written practice too?

Everything on this page is free and always will be. If you want structured worksheets to go alongside it, the 5th Grade packs cover the whole year across maths, reading and writing, and study skills.

5th Grade Packs

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Frequently Asked Questions

What should a 5th Grade child understand about money?

Money you leave alone grows on its own — and money you borrow shrinks the same way. Concretely: calculates compound interest year by year without a formula; explains why early saving beats larger later saving; uses cost per use rather than price to compare purchases. The six lessons on this page cover each of those, and the money check tells you which ones have landed.

How much allowance should a 5th Grade child get?

Around $10 a week is a reasonable starting point at ages 10–11. About $10 a week. At this level the grow jar can fund a genuine venture, which is the point of raising it. The calculator on this page lets you try different amounts and splits.

What business can a 5th Grade child actually run?

The One-Page Business: "Here's the plan, in writing, before I spend a cent." Startup cost is $0 to plan; set your own cap before you start. The gap between planned numbers and real numbers is where all the learning is. Plans are wrong; planning still pays.

What is the most common money mistake 5th Grade children make?

Hearing this and concluding hourly work is a mistake. Rafa ate for a year on nothing, which only worked because he was twelve and living at home. Do both. Trade time for the money you need now, and spend a slice of that time building something that keeps paying. Each of the six lessons on this page names the trap for its own pillar and the smallest change that fixes it.

Is the 5th Grade money content on this page free?

Yes — all 6 lessons and their pictures, the 8-question check, the 6 stories, the 3 decision cards, the 4 worked money sums, the questions to ask at dinner, the vocabulary, the mission, the starter business, the allowance calculator, and the milestones are free with no signup. The 5th Grade printable packs in the shop are optional.

Does this work for a child who cannot read yet?

Every lesson on this page has a picture as well as words, so a younger sibling can follow along. If your child is not reading independently yet, start at the Pre-K or Kindergarten page instead — those are built to be spoken and pointed at.

5th Grade — Money & Business

5th Grade — Money & Business

For grown-ups: 5th Grade money

🍽️ Four questions to ask this week

Three habits that matter at this age

Show them the curve, don't describe it

Write plans before spending money

Compare plan to reality afterwards

✅ By the end of 5th Grade

Want the written practice too?

Frequently Asked Questions

What should a 5th Grade child understand about money?

How much allowance should a 5th Grade child get?

What business can a 5th Grade child actually run?

What is the most common money mistake 5th Grade children make?

Is the 5th Grade money content on this page free?

Does this work for a child who cannot read yet?

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Four questions to ask this week

By the end of 5th Grade