How many doubles does it take?
Start with £1. Double it. Double it again. How many doubles until you pass £1,000,000?
Most grown-ups get this very wrong. Write your number down before you press.
Inside the book
Every time you turn the page, your pound doubles. Twenty-one chapters, one page each, from a pound down the back of the sofa to the million-pound page. And every sum in it can be checked by a ten-year-old with a pencil. That's a promise.
It's a game
Everyone playing starts with £1 — you included. Spend, and you go all the way back to the start.
Check the maths
The dog-walking race, the Freddo, the money machine: don't believe the book. Count for yourself.
Meet Sid & Sage
Sid likes to spend. Sage likes to save. One of them wins the summer. It isn't who you think.
Are you a Sid or a Sage?
Be honest. The game is about to test you.
The book
Written by Rob Dunfey, who was given a grown-up money book at the age of ten. He understood only half of it, but loved all of it. This book is his way of passing that gift on.
- Ages 8–12 · one page per chapter
- Flick the corner and watch the acorn grow
- British edition in £ · US edition to follow in $
A quick word on price: Gumroad lets you pay what you want, including £0. £5 is the suggested amount if you'd like to say thanks, but what I'd genuinely love more than that is your honest feedback. Read it, tell me what you think, send it to feedback@howmanydoubles.com, that's the real currency right now.