In this chapter, you learned about the various methods that can be used to output data. You saw the advantages of echo for short amounts of output and its disadvantages for longer amounts of outputespecially static output. You've also had a chance to explore using the short equals operator to splice dynamic content into static output. And, lastly, you examined input, both with the get and post methods, and the advantages and disadvantages of each.
Now that you have a good idea of how to collect input, you're ready to move towards manipulating the data you've collected. This includes everything from taking input and doing arithmetic operations on it to examining an e-mail address to decide whether it's valid. The most basic sort of data manipulation is arithmetic, so it makes sense that we'll start there. In the next chapter, you learn how to perform basic arithmetic operations, as well as learn that some very interesting things can be done with arithmetic.