32 Calculator Keystroke Guide
Suppose instead that you want your calculator to automatically round computations to a fixed
number of decimal places. Press the MODE key again. The second line of the Mode screen reads
Float 0123456789. To make the calculator automatically round all calculations to two
decimal places, on the second line of the MODE screen use the arrow keys to move the blinking
cursor over the number 2 and press ENTER. Press 2nd [QUIT] to return to the Home screen. Now if
you do the same three computations above again, the calculator will display the results rounded
with only two digits to the right of the decimal point (that is, rounded to the nearest hundredth):
17÷8 = 2.13, 368÷7 = 52.57, and 9543÷7 = 1363.29. When you are through making the
calculator round to two decimal places, it would probably be best to return to the MODE menu and
change the setting back to Float.
page 4
3 Square Root
The square root is the second function on the
2
key. (Note the square root sign ð printed above
the
2
key in yellow print.) To produce a square root sign on the Home screen display, first press
the yellow 2nd key and then press the
2
key to produce its second function, the square root sign.
In the future, this key sequence will be denoted 2nd [ ð ] , where the second function of the key is
enclosed in brackets. Other keystrokes involving the 2nd key will be denoted in a similar fashion.
The expression in the brackets should be found printed above one of the keys on the keyboard.
Note that what actually appears on the screen is the square root sign, followed by an open
parenthesis: ð(. The number or mathematical expression whose square root you wish to evaluate
is called the argument of the square root. The TI-83 requires that the argument of the square root
be enclosed in parentheses. The calculator does you the favor of typing the open parenthesis for
you. After you have typed in the number or expression, you should end it with a close parenthesis:
).
Unlike with most scientific calculators, with the graphing calculator you enter the square root
sign first. To find the square root of 324, use the following keystrokes: 2nd [ ð ] 324) ENTER. On
the Home screen you will see ð(324). The value of this square root, 18, should have appeared
on the right of the screen after you pressed ENTER.
Note that the calculator does the square root of the number or expression enclosed in
parentheses immediately following the square root sign. If you want to compute 187 + , you
should group the sum in parentheses, ð(7+18), to indicate that the sum is to be computed before
the square root is taken. (The correct value of this expression is 5.) If you want to compute the
value of 79 + , where the square root is to apply only to the number 9, you must be sure to put
a close parenthesis after the 9 when you enter this expression into the calculator: ð(9)+7. The
value of this expression is 10. If you forget to type the close parenthesis, the calculator will
assume that you wanted a close parenthesis at the end of the expression. Thus, in the last
example the calculator would interpret ð(9+7 as being the same as ð(9+7), which is the square
root of 16, or 4.
page 11
4 Add
The addition key + is on the right-hand side of the keyboard with the other basic operation keys
(subtraction, multiplication, and division). Basic addition is done as it is on most other kinds of
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