Enter r the number of items selected from the set and press ENTER to display the result. Using the TI-84 Plus you must enter n insert the command and then enter r. On the Home screen enter n the total number of items in the set.
In the first blank enter n the total number of items in the set.
You should see X02 on the screen. Fill in the needed information highlight paste and then press enter. If its not and it probably isnt press you should see the word CATALOG above the key. Then choose the MATH menu.