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Full Version: HP 10BII Combination Permutation
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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
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