There are an estimated 1.618 million web sites dedicated to recreational mathematics.  Many of them feature interesting and useful material, but there is mammoth duplication of content.  I strongly desire not to contribute to the clutter, hoping to offer perspectives sufficiently unique that they will not be encountered elsewhere.

Doubtless these materials will interest only a small percentage of visitors.  No advanced learning is required here, however; a reasonable awareness of high-school math is sufficient.

A Challenge to Mathematicians:  Solve the "Black Box" Puzzle

A Special Continued Fraction for Square Roots

Pencil & Paper Square Roots Using Continued Fractions

Some Tips & Tricks for Mental Calculations

Be Your Own Perpetual Calendar — Calculate Dates in Your Head

The articles in this section are designed to be assimilated in numeric sequence.  Each page features ideas or methods previously introduced.

1: Introduction to Programming a Four-Function Calculator

2: Integer Powers

3: Integer Roots

4: Trigonometry

5: Compound Interest

6: Logarithms

7: Extra Decimals for Square Roots

8: Some Arithmetic Shortcuts

Squaring the Square

Black Box math challenge
Newton-Raphson
Babylonian Heron
square root iteration
Fibonacci
continued fraction
mental arithmetic
mathematics
pencil and paper
compound interest
logarithms
trigonometry
4-function calculator
Taylor series
arithmetic shortcuts
squared square