HP 15c Scientific manual Order of Entry and the v Key, +15 X15

Section 3: The Memory Stack, LAST X, and Data Storage 37

T	z
Z	z
Y	y
X	7

Keys:

z

z

y

0

` 6

lost

z

z

y

6

z

z

y

y6

Y

Order of Entry and the v Key

An important aspect of two-number functions is the positioning of the numbers in the stack. To execute an arithmetic function, the numbers should be positioned in the stack in the same way that you would vertically position them on paper. For example:

98	98	98	98
-15	+15	x15	15

As you can see, the first (or top) number would be in the Y-register, while the second (or bottom) number would be in the X-register. When the mathematics operation is performed, the stack drops, leaving the result in the X-register. Here is how a subtraction operation is executed in the calculator:

T

Z

Y

X Keys:

t

z

y

x

lost

z

y

x

98 98

lost

y

x

98

98

v15

y

x

98

15

y

y

x

83

-

The same number positioning would be used to add 15 to 98, multiply 98 by 15, or divide 98 by 15.