# Magic Number (Infinite Series)

What if you made a series of unit fractions with the odd numbers as their denominator, added the first two together, subtracted the next one, added the next one and so on. And finally multiplied that number by 4? What number would you get?

# Inverse Variation

The variables in most of the functions we are used to working with vary directly, as one goes up the other goes up. What do functions that vary inversely, when one variable goes up the other goes down, look and act like?

# GDP

The GDP or Gross Domestic Product of a country is one measure of its wealth. What can this data tell us about the U.S. economy? Are we getting wealthier? Are each of us really wealthier after inflation? What else does this data tell you?

# Parametric Equations

Parametric equations are powerful tools to model projectile motions and to graph things that are not functions like circle or ellipses. The x and y coordinates are defined as two separate functions with a common independent variable often labelled “t”.

# Solar System

When I was young I loved to play with planetary data, to explore their patterns, to learn more about astronomy, and to deal with large numbers. Spreadsheets make it much easier to study the solar system and to find relationships between the planets that are fascinating and unexpected. In the process you will not only learn more science, you will gain spreadsheet skills working with data and functions.