
Section 3: Automatic Memory Stack and ALPHA Register49


The simple oldfashioned math notation helps explain how to use your
calculator. Both numbers are always positioned in the calculator in the
natural order first, then the operation is executed. There are no
exceptions to this rule. Subtraction, multiplication, and division
work the same way. In each case, both numbers must be in the proper
position before the operation can be performed.


Chain Calculations


You’ve already learned how to key numbers into the calculator and perform
calculations with them. In each case you first needed to position the numbers
in the stack manually using the ENTER key. However,
the stack also performs many movements automatically. These automatic
movements add to its computing efficiency and ease of use, and it is these
movements that automatically store intermediate results. The stack automatically
‘‘lifts’’ every calculated number in the stack when a new
number is keyed in because it knows that after it completes a calculation, any
new digits you key in are part of a new number. Also, the stack automatically
‘‘drops’’ numbers into position when you perform
twonumber operations.


To see how it works let’s solve 21 + 38 + 19 + 53 = ?


For purposes of simplification, this example shows the stack cleared to
zeros.




T

0.0000


Z

0.0000


Y

0.0000

(Displayed)

X

21 _

T

0.0000


Z

0.0000


Y

21.0000

(Displayed)

X

21.0000

T

0.0000


Z

0.0000


Y

21.0000

(Displayed)

X

38 _

T

0.0000


Z

0.0000


Y

0.0000

(Displayed)

X

59.0000

T

0.0000


Z

0.0000


Y

59.0000

(Displayed)

X

19 _

