how to do ncr on ti-84?
['Step 1: Type in the first number. In this case, the first number is 25.', 'Step 2: Press [MATH] and go to the PRB menu. You can use the right arrow to select the menu at the top.', 'Step 3: Select 3 nCr and press [ENTER] ... ', 'Step 4: Type the second number and press [ENTER]']