The Square in Your Head
The idea: squaring near a round number, and why the little square is added back.
Read it
Who is in this book
-
Squarl To square an awkward number, bounce to a round one and back, then add the square of the bounce from ShowMath -
Marlow Rehearse, perform, then reveal the reason instead of protecting the mystery from ShowMath -
Danya a child of the Green Asks "how do we know?" -
Beto a child of the Green Takes things apart
Every recurring character has a short tune, so you can tell who is on stage before a word is said. The tunes play only when you tap, and the Reading Access sound switch turns them off.
The Honest Page
Which parts of this story are true, stretched or made up?
True
- 47 × 47 = 2209, and 44 × 50 + 9 = 2209. Going up and down by the same amount and multiplying always gives one little square less than the true square.
- This is the rule (a + b)(a − b) = a² − b², which can be shown by cutting and moving a strip of a square, as Danya does. Source
Stretched
- Squarl does it in two seconds. What we simplified: Fast mental calculators practise for a long time; most people need a little longer, and that is fine.
Made up
- The Open Hand troupe and its wagon are made up. Squarl and Marlow come from ShowMath.
Tell it back
Tell the story in your own words: who was there, what went wrong, and what they found out. Then the fourth lock on the troupe's trunk goes on your belt.
On your belt: the fourth lock on the troupe's trunk.
Your belt lives on this device. Nothing is sent anywhere.
Ring the hammer for someone
Pick this book for someone younger. The link carries only the book, and it will wait for them on the Green.