The finance app is one of 16 apps included on Texas Instrument's TI-89 graphing calculator. The finance app is a worksheet-style app that helps you solve financial equations. So if you need to find out how much interest you could make on an investment or how much of your monthly payment goes toward your loan's principal, you should give your TI-89's finance app a try.
Power on your TI-89 by pressing the "On" button.
Press the calculator's "App" button. Select the "Finance" option from the menu with the TI-89's directional keypad then press the "Enter" button to enter the "Finance" mode.
Use the TI-89's directional keypad to move up or down in the finance app's fields. Use the numerical keypad to enter a value into one of the fields. Enter values for at least four of the finance app's fields.
Highlight the "End" option, located next to the "PMT" heading. Press the TI-89's "F2" button to find out the unknown variable in your financial equation and the value of your money over the life of the investment.