How do you calculate permutations on the TI-$84$?

Hint: Here in this question, we have to find out how to calculate permutations on the TI-$84$. Before proceeding and solving the given question we should know what is permutation. The arrangement of objects in a definite order is known as permutation. The formula for calculating permutation is ${}^n{P_r}$. It is denoted by ${}^n{P_r} = \dfrac{{n!}}{{\left( {n - r} \right)!}}$.

Formula used:
Permutation: ${}^n{P_r} = \dfrac{{n!}}{{\left( {n - r} \right)!}}$

Complete step by step answer:
One important thing to know before finding out how to calculate permutations on TI-$84$calculator is that TI-$84$is a calculator which can be used to calculate permutation and combination. The arrangement of objects in a definite order is known as permutation. It is denoted by ${}^n{P_r} = \dfrac{{n!}}{{\left( {n - r} \right)!}}$
In the TI-$84$calculator to calculate permutation, we will first enter the larger number i.e.,$n$(the number of total cases to choose from). Then, we will enter the${}^n{P_r}$function. After that, we will select the number to be chosen $r$.
We use${}^n{P_r}$if the order of selecting is important but if order of selecting isn’t important then we can use${}^n{C_r}$(C for combinations) in the same menu. We can say that,
$ \Rightarrow {}^n{P_r} = {}^n{C_r}\left( {r!} \right)$
That is how we can calculate permutation on the TI-$84$.

Note: The TI-$84$ calculator can also be used to calculate combinations. The $!$ in $r!$ refers to factorial. Factorial is a multiplication of all numbers up to and including $r$. For example-$3! = 3 \times 2 \times 1 = 6$. The common error while calculating permutations on the TI-$84$ calculator is entering the wrong values of $n$ and $r$.