www.numberpower.org 
Expressions 

To play the movie, the Flashplayer must be installed. Your browser needs to be configured to use the FlashPlayer as an application (see your browser preferences). If you are using Internet Explorer for Windows, you must install the latest Flash Active Plug in.

Expressions consists of: variables (another name for letters)  always h = variable a coefficient (the number in front of a variable) sometimes 2k coeffient and variable an operation sign (tells you what to do) sometimes +  x / a constant (number that stands alone  sometimes c + 6 equal sign  never 
Variables can be simplified c + c + c becomes 3c Notice the variable is never capitalized. 3(h + 5) becomes 3h = 5 m (a + 4) becomes am + 4m z (9  n) becomes 9z  nz 4g + 6 g becomes 10 g 19b  8b becomes 11b If d is 7 then 4d becomes 4 x 7 = 28 Easy isn't? 
