Permutations and Combinations
The permutation of n things taken r at a time, nPr,
is calculated as follows. For 5P3 enter
5 
and press 
three times to select PRB.
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 6C4 enter
6
and press three times to select PRB.
Then, select nCr by pressing 
. Enter the value of r,
which is 4 and press .
