How to calculate permutations on TI-84 calculator?

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Calculating permutations on a TI-84 calculator can be done using the built-in nPr (Permutation) function. Here’s how you do it:

  1. Access the Math Menu: Press the MATH button to access the Math menu.
  2. Select the Permutation Function: Use the arrow keys to navigate to the PROB column, and select 2:nPr and press ENTER. This will open the permutation function.
  1. Enter the Values:
    • Enter the total number of items nn.
    • Enter the number of items to arrange rr.
  2. Perform the Calculation: After entering nn and rr, press ENTER again to calculate the number of permutations.

The calculator will display the result, which is the number of ways to arrange rr items from a set of nn items where the order of selection matters.

Here’s an example: If you want to calculate the number of permutations for arranging 3 items from a set of 5, you would:

  • Press MATH to access the Math menu.
  • Choose PROB, select 2:nPr and press ENTER.
  • Enter 5 for nn and 3 for rr.
  • Press ENTER to get the result.

The TI-84 calculator will then display the number of permutations, which in this case is calculated using the formula P(n,r)=n!(n−r)!P(n,r)=(n−r)!n!​

, and for our example, it would be 5!(5−3)!=60(5−3)!5!​=60.

Remember that the permutation formula is n!(n−r)!(n−r)!n!​, where !! denotes factorial, and rr is typically less than or equal to nn. The calculator performs this calculation for you when you use the nPr function.

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