HP 10BII Combination Permutation

[Gamo]

HP 10BII+ got this functions but not for the HP 10BII

HP 10BII User Manual doesn't provide the way to calculate this and
here is my attempt.

Formulas:

Permutation: nPr = n! ÷ [ (n - r)! ]

Combination: nCr = n! ÷ [ r! x (n - r)! ]

Example:

6P3

6 [-] 3 [=] [n!] [÷] 6 [n!] [SWAP] [=] display answer 120

6C3

6 [-] 3 [=] [n!] [x] 3 [n!] [=] [÷] 6 [n!] [SWAP] [=] display answer 20

Remark:

The Factorial Function limit is up to 253! = 5.17 E499


Gamo 7/2021

[Gamo]

Update key steps for both the "Combination and Permutation" by the use

of the memory key [→M]

Example:

►A child has a set of toy blocks with the 26 letters of the alphabet each appearing once.
How many different three-letter permutation ( 26P3 ) can be made with these blocks?

26 [→M] [-] 3 [=] display 23.00 [n!] display 2.59 E22 [÷] [RM] [n!] display 4.03 E26

[SWAP] [=] display answer 15,600.00

►A manager wants to choose a committee of three people from the seven engineers working for him.
In how many different ways cn the committee be selected? ( 7C3 )

7 [→M] [-] 3 [=] display 4.00 [n!] display 24.00 [x] 3 [n!] [=] display 144.00

[÷] [RM] [n!] display 5,040.00 [SWAP] [=] display answer 35.00


Gamo