I actually used algebra in a (sort-of) real world application today, to the astonishment of seventh-graders everywhere. I was writing a content management tool for the Twist Magazine homepage, and wanted to make a “preview” function that showed what a component would look like — *before* saving that component to the SQL server database. So the script looked at the value of input boxes in given forms, using the forms array. Problem is that each element has at least three forms, but the first element has only two forms. So, to make a long story long, I had to map the numbers 2,3,4,5, et cetera, to the numbers 3,7,11,15,19, and so on. I was scratching my head for a long time, until I remembered to use slope-intercept form — y=mx+b — to figure out the function. Voila, the second number is four times the first minus five, done. Go home, watch the Simpsons, hooray!