## Permutations and Combinations

The permutation of n things taken r at a time, nPr,
is calculated as follows.
For _{5}P_{3} enter
5
and press followed by
to select PROB.
Then, select nPr by pressing
.
Enter the value of r,which is 3, and press
.

The combination of n things taken r at a time, nCr,
is calculated as follows. For _{6}C_{4} enter
6 and press
followed by three
to select PRB.
Then, select nCr by pressing .
Enter the value of r,which is 4, and press .