For a teacher a calculator can be the worst thing in the classroom, in other classes the calculator can be a helpful tool for simplifying problems, graphing strange equations, and overall confusion in math. Most students don't know their way around a normal calculator that adds/subtracts/multiplies/divides let alone a graphing calculator that can do multiple functions. Here is a website that shows you how to use the graphing calculator, especially the TI 83/84. http://mathbits.com/mathbits/tisection/openpage.htm this website covers all the math areas from algebra, calculus, trigonometry, geometry, and statistics. There is also a teacher page, a robot page, and problem/solving techniques on your graphing calculator.
Graphing calculators help students visualize problems and discover mathematical theorems on their own.