Grades 4–10
Why Does Math Work?
The rules everyone memorizes — and why they are true. Each lesson shows the reason in a picture or a short argument.
Where Do Area Formulas Come From?
0.999… = 1? Two Simple Proofs That 0.99999 Equals 1
Why Is a Triangle 180 Degrees? (And Why 360 in a Circle?)
Why Is Negative Times Negative Positive? (2 Proofs)
Why Can't You Divide by Zero? (A Warship Found Out)
Why Is Anything to the Power of 0 Equal to 1? (Zero Exponent Rule)
Where Does Pi Come From? 3 Ways to See 3.14
