On PHPBuilder.com today they've posted the next article in their "ABCs of PHP" series. This time they focus on math and number handling.

Last time we looked at text and strings in variables, in this episode we're going to continue with our exploration of PHP variables and delve deeper into math and number handling in PHP. Using numbers is not much different to using text and strings, you allocate variables and fill them in, using exactly the same techniques as you do using strings & text.

They covers some of the basic operators (+,-,*,etc), evaluation with equals, number shifting, binary and creating a "barrel shifter" to work with the binary bits of a number.