Storing And Recalling Numbers - HP 20B User Manual

nCr

nPr

x
Y is the power function, nCr stands for the number of combinations of n items taken r at a time, and nPr stands for the
number of permutations of n items taken r at a time.
n !
Combination=
 

r ! n r !
n !
Permutation=
 

n r !
Perform calculations with these functions in the same way you would perform calculations with
:
but press to access the secondary function key. For example, to calculate 15
15
1. Press
:h
2. Press
3=
3. Press
In RPN mode, key in the numbers first, followed by
example above, in RPN press:

Storing and Recalling Numbers

The calculator has ten memories available for use during calculations. These memories are numbered from 1-9 and 0. To
store a number in a memory, press
stored in a memory, press
functions for these memories any time a number is displayed, or when you wish to enter a number.
For example, to store 15 in memory 1, press
To recall the number in memory 1, press
You can also perform operations to numbers stored in memories. For example, press
memory 2. To add 12 to the value of memory 2, press
.
.
. The results are shown Figure 9.
15I3:h
:$
, followed by the key representing the memory number. To recall a number
L
followed by the key representing the memory number. You can use the store and recall
15:$1
L1
Figure 9
I
, then press the function key. For example, for the power function
.
.
.
12:$+2
27
Mathematical Calculations
+-/
3
:
5:$2
. Later on, during a calculation, you can
*
and ,
to store 5 in