HP 20B manual Storing and Recalling Numbers

Mathematical Calculations

nCr

nPr

Y x 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 +-/and *, but press :to access the secondary function key. For example, to calculate 153 :

1.Press 15.

2.Press :h.

3.Press 3=. The results are shown Figure 9.

Figure 9

In RPN mode, key in the numbers first, followed by I, then press the function key. For example, for the power function example above, in RPN press: 15I3:h.

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 :$, followed by the key representing the memory number. To recall a number stored in a memory, press Lfollowed by the key representing the memory number. You can use the store and recall 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 15:$1.

To recall the number in memory 1, press L1.

You can also perform operations to numbers stored in memories. For example, press 5:$2to store 5 in

memory 2. To add 12 to the value of memory 2, press 12:$+2. Later on, during a calculation, you can

27