The TI-83 is a graphing calculator that is used for mathematics; sigma is the Greek letter used in math used to designate summations. With a given function and limit, you can easily enter a summation equation into your TI-83 and solve for sigma. This way you can avoid having to solve the equation by hand and save time.

Press and hold the "2nd" button, then press "STAT."

Scroll to the right to the "MATH" option, then press "5."

Press and hold the "2nd" button then press "STAT."

Scroll to the right to select the "OPS" option, then press "5." You will now have "Sum(Seq(" on your screen.

Enter the equation to the right of igma, then add a comma. For example, if the equation is 3x+2, then type "3x+2," into the TI-83.

Enter the value of x followed by a comma. This is located under the sigma symbol in the equation. For example, if in the equation is says "x=5" then type "5," into the calculator.

Enter the value above the Sigma symbol. Follow the value with a comma. If the value in your equation is 7, then you would enter "7,"

Enter "1" and finish with "))." If entered properly, your calculator would read something like this: "Sum(Seq(3x+2,X,5,7,1))"

Press the "Enter" key to solve for sigma.