Last Number - HP 20B User Manual

When an operation is performed on the stack, addition
from the bottom levels (Levels 1 and 2) out of the stack, performs the operation, and "pushes" the results back into the stack.
With the numbers entered into the stack as shown in Figure 3, pressing
that when the numbers are "popped" out to add 23 and 41, Level 4 of the stack remains unchanged.

Last Number

Each time you perform a mathematical operation, the content of Level 1 of the stack is saved. Pressing
number. This functionality can be used to undo an erroneous key press, or if you want to reuse a number, such as 56.123 in
the expression:
 

. 1 23 56 . 123
 
56 . 123
See Table 2-2 for an example using the last number function.
Table 2-2 Last Number
Keys
:u3I
<<<<<
II
O1c23
I56c1
23
(+)
Figure 4 The RPN Stack of Figure 3 after the Addition Operation
Display
19
Mathematical Calculations
for instance, the calculator "pops" or moves the two numbers
+
changes the stack as shown in Figure 4. Note
-15
-15
12
64
Description
Sets FIX= to 3.000
Selects RPN as the operating mode.
Inputs 1.23 and 56.123
:d
recalls that