Appendix C
Using a Calculator
and Computer Keypad
Kinds of Calculators
manual for specific instructions and locations of the
operating keys for the calculator being used. A typical keyboard of a desktop calculator is shown in the
illustration.
Many different models of calculators, both desktop
and handheld, are available. All calculators have their
own features and particular placement of operating
keys. Therefore, it is necessary to refer to the operator’s
DISPLAY
OPERATING
SWITCHES
+
➞
➞
5/4
0
2
3
4
F
PRINT
GT
NON-ADD
KEY
%
OPERATION
KEYS
4
CE
/C
7
8
9
–D#
4
5
6
1
2
3
00
?
5
3
0
2
➞
CA
M*
PAPER ADVANCE
KEY
N M2
MEMORY
KEYS
M1
1
*
M
TOTAL
KEY
NUMBER
SUBTOTAL
KEYS
DECIMAL OPERATION KEY
KEYS
POINT
Desktop Calculator Settings
Several operating switches on a desktop calculator
must be engaged before the calculator will produce the
desired results.
The decimal selector sets the appropriate decimal
places necessary for the numbers that will be entered.
For example, if the decimal selector is set at 2, both the
numbers entered and the answer will have two decimal
places. If the decimal selector is set at F, the calculator
automatically sets the decimal places. The F setting
allows the answer to be unrounded and carried out to
the maximum number of decimal places possible.
The decimal rounding selector rounds the answers.
The down arrow position will drop any digits beyond
the last digit desired. The up arrow position will drop
any digits beyond the last digit desired and round the
last digit up. In the 5/4 position, the calculator rounds
Using a Calculator and Computer Keypad
Appendix C
C-1
the last desired digit up only when the following digit is
5 or greater. If the following digit is less than 5, the last
desired digit remains unchanged.
The GT or grand total switch in the on position accumulates totals.
Kinds of Computer Keyboards
The computer has a keypad on the right side of the keyboard, called the numeric keypad. The two basic layouts
for the numeric keypad, standard and enhanced, are
shown in the illustration. On the standard keyboard,
the directional arrow keys are found on the number
keys. To use the numbers, press the key called Num
Lock. (This key is found above the 7 key.) When the
Num Lock is turned on, numbers are entered when the
keys on the keypad are pressed. When the Num Lock
is off, the arrow, Home, Page Up, Page Down, End,
Insert, and Delete keys can be used.
The enhanced keyboards have the arrow keys and
the other directional keys mentioned above to the left
of the numeric keypad. When using the keypad on an
enhanced keyboard, Num Lock can remain on.
The asterisk (*) performs a different function on the
computer than the calculator. The asterisk on the calculator is used for the total while the computer uses it for
multiplication.
Another difference is the division key. The computer
key is the forward slash key (/). The calculator key uses
the division key (8).
Num Lock Key
Division Key
Multiplication Key
0
Ins
End
Page
Down
6
+
3
Pg Dn
?
Del
8
Home
4
➞
2
7
/
*
1
Enter
Standard
Keyboard Layout
End
➞
0
Ins
–
9
➞
Delete
Num
Lock
5
Pg Up
6
+
➞
2
3
➞
5
➞
End
Page
Up
Pg Up
➞
1
Home
➞
4
Insert
➞
Home
–
9
➞
8
*
➞
7
/
➞
Num
Lock
Pg Dn
?
Del
Enter
Enhanced
Keyboard Layout
Ten-Key Touch System
Striking the numbers 0 to 9 on a calculator or numeric
keypad without looking at the keyboard is called the
touch system. Using the touch system develops both
speed and accuracy.
The 4, 5, and 6 keys are called the home row. If
the right hand is used for the keyboard, the index
finger is placed on the 4 key, the middle finger on
the 5 key, and the ring finger on the 6 key. If the left
hand is used, the ring finger is placed on the 4 key,
the middle finger on the 5 key, and the index finger
on the 6 key.
C-2
Appendix C
Place the fingers on the home row keys. Curve the
fingers and keep the wrist straight. These keys may
feel slightly concaved or the 5 key may have a raised
dot. The differences in the home row allow the operator to recognize the home row by touch rather than
by sight.
Maintain the position of the fingers on the home
row. The finger used to strike the 4 key will also strike
the 7 key and the 1 key. Stretch the finger up to reach
the 7; then stretch the finger down to reach the 1 key.
Visualize the position of these keys.
Using a Calculator and Computer Keypad
Again, place the fingers on the home row. Stretch the
finger that strikes the 5 key up to reach the 8 key, then down
to reach the 2 key. Likewise, stretch the finger that strikes the
6 key up to strike the 9 and down to strike the 3 key. This
same finger will stretch down again to hit the decimal point.
If the right hand is used, the thumb will be used to
strike the 0 and 00 keys and the little finger to strike the
addition key. If the left hand is used, the little finger will
be used to strike the 0 and 00 keys and the thumb to
strike the addition key.
Handheld Calculators
Handheld calculators are slightly different from desktop calculators, not only in their size and features
but also in their operation. Refer to the operator’s
manual for specific instructions for the calculator
being used.
On a handheld calculator, the numeric keys are usually very close together. In addition, the keys do not
respond to touch as easily as on a desktop calculator.
Therefore, the touch system is usually not used on a
handheld calculator.
Performing Mathematical Operations on Desktop Calculators
Mathematical operations can be performed on a calculator both quickly and efficiently. The basic operations
of addition, subtraction, multiplication, and division
are used frequently on a calculator.
ADDITION
Each number to be added is called an addend. The
answer to an addition problem is called the sum.
Addition is performed by entering an addend and
striking the addition key (
). All numbers are entered
on a calculator in the exact order they are given. To enter
the number 4,455.65, strike the 4, 4, 5, 5, decimal, 6,
and 5 keys in that order, and then strike the addition
key. Commas are not entered. Continue in this manner
until all addends have been entered. To obtain the sum,
strike the total key on the calculator.
SUBTRACTION
The top number or first number of a subtraction problem is called the minuend. The number to be subtracted
from the minuend is called the subtrahend. The answer
to a subtraction problem is called the difference.
Subtraction is performed by first entering the minuend and striking the addition key (
). The subtrahend
is then entered, followed by the minus key (<), followed
by the total key.
MULTIPLICATION
The number to be multiplied is called the multiplicand.
The number of times the multiplicand will be multiplied
is called the multiplier. The answer to a multiplication
problem is called the product.
Multiplication is performed by entering the
multiplicand and striking the multiplication key (=).
The multiplier is then entered, followed by the equals
key (). The calculator will automatically multiply and
give the product.
DIVISION
The number to be divided is called the dividend. The
number the dividend will be divided by is called the
divisor. The answer to a division problem is called the
quotient.
Division is performed by entering the dividend and
striking the division key (8). The divisor is then entered,
followed by the equals key (). The calculator will automatically divide and give the quotient.
CORRECTING ERRORS
If an error is made while using a calculator, several methods of correction may be used. If an incorrect number
has been entered and the addition key or equals key has
not yet been struck, strike the clear entry (CE) key one
time. This key will clear only the last number that was
entered. However, if the clear entry key is depressed more
than one time, the entire problem will be cleared on some
calculators. If an incorrect number has been entered and
the addition key has been struck, strike the minus key
one time only. This will automatically subtract the last
number added, thus removing it from the total.
Performing Mathematical Operations on Computers and Handheld Calculators
On a computer keypad or a handheld calculator, addition is performed in much the same way as on a desktop
calculator. However, after the key is depressed, the
display usually shows the accumulated total. Therefore,
the total key is not found. Some computer programs
will not calculate the total until Enter is pressed.
Using a Calculator and Computer Keypad
Appendix C
C-3
Subtraction is performed differently on many computer keypads and handheld calculators. The minuend is
usually entered, followed by the minus (<) key. Then the
subtrahend is entered. Pressing either the key or the key will display the difference. Some computer programs
will not calculate the difference until Enter is pressed.
Multiplication and division are performed the same
way on a computer keypad and handheld calculator as
on a desktop calculator. Keep in mind that computers
use the * for multiplication and / for division.
Safety Concerns
Whenever electrical equipment such as a calculator or
computer is being operated in a classroom or office, several safety rules apply. These rules protect the operator
of the equipment, other persons in the environment,
and the equipment itself.
1. Do not unplug equipment by pulling on the electrical cord. Instead, grasp the plug at the outlet and
remove it.
2. Do not stretch electrical cords across an aisle where
someone might trip over them.
3. Avoid food and beverages near the equipment where
a spill might result in an electrical short.
4. Do not attempt to remove the cover of a calculator, computer, or keyboard for any reason while the
power is turned on.
5. Do not attempt to repair equipment while it is
plugged in.
6. Always turn the power off or unplug equipment
when finished using it.
Calculation Drills
INSTRUCTIONS FOR DESKTOP CALCULATORS
Complete each drill using the touch method. Set the
decimal selector at the setting indicated in each drill.
Compare the answer on the calculator to the answer in
the book. If the two are the same, progress to the next
problem. It is not necessary to enter 00 in the cents
column if the decimal selector is set at 0-F. However,
digits other than zeros in the cents column must be
entered, preceded by a decimal point.
INSTRUCTIONS FOR COMPUTER KEYPADS
Complete each drill using the touch method. There
is no decimal selector on computer keypads. Set the
number of decimal places as directed in the instructions
for the computer program. In spreadsheets, for example,
use the formatting options to set the number of decimal places. When the drill indicates “F” for floating,
leave the computer application in its default format.
Compare the answer on the computer monitor to the
answer in the book. If the two are the same, progress to
the next problem. It is not necessary to enter 00 in the
cents column. However, digits other than zeros in the
cents column must be entered, preceded by a decimal
point.
DRILL C-1 Performing addition using the home row keys
Decimal Selector—2
C-4
4.00
5.00
6.00
5.00
4.00
5.00
6.00
5.00
4.00
5.00
44.00
55.00
66.00
45.00
46.00
54.00
56.00
65.00
64.00
66.00
444.00
555.00
666.00
455.00
466.00
544.00
566.00
655.00
644.00
654.00
4,444.00
5,555.00
6,666.00
4,455.00
4,466.00
5,544.00
5,566.00
6,655.00
6,644.00
6,545.00
44,444.00
55,555.00
66,666.00
44,556.00
44,565.00
55,446.00
55,664.00
66,554.00
66,555.00
65,465.00
49.00
561.00
5,649.00
56,540.00
565,470.00
Appendix C
Using a Calculator and Computer Keypad
DRILL C-2
DRILL C-3
DRILL C-4
DRILL C-5
Performing addition using the 0, 1, 4, and 7 keys
Decimal Selector—2
4.00
7.00
4.00
1.00
4.00
7.00
4.00
1.00
4.00
7.00
11.00
44.00
74.00
71.00
70.00
10.00
14.00
17.00
40.00
77.00
444.00
777.00
111.00
741.00
740.00
101.00
140.00
701.00
700.00
407.00
4,440.00
7,770.00
1,110.00
4,400.00
1,100.00
4,007.00
7,001.00
1,007.00
1,004.00
7,700.00
44,000.00
77,000.00
11,000.00
41,000.00
71,000.00
10,000.00
10,100.00
40,100.00
70,100.00
74,100.00
43.00
428.00
4,862.00
39,539.00
448,400.00
Performing addition using the 2, 5, and 8 keys
Decimal Selector—2
5.00
8.00
5.00
2.00
5.00
8.00
5.00
2.00
5.00
8.00
58.00
52.00
85.00
52.00
25.00
58.00
82.00
28.00
88.00
22.00
588.00
522.00
888.00
222.00
258.00
852.00
225.00
885.00
882.00
228.00
8,888.00
5,555.00
2,222.00
8,525.00
2,585.00
8,258.00
8,585.00
5,258.00
2,852.00
2,288.00
88,855.00
88,822.00
88,852.00
88,222.00
85,258.00
22,255.00
22,288.00
22,258.00
22,888.00
25,852.00
53.00
550.00
5,550.00
55,016.00
555,550.00
Performing addition using the 3, 6, 9, and decimal point keys
Decimal Selector—2
6.00
9.00
6.00
3.00
6.36
3.36
9.36
9.63
6.33
9.93
66.66
99.99
33.33
33.66
33.99
99.66
99.33
33.36
33.69
69.63
666.66
999.99
333.33
666.99
999.66
333.66
696.36
369.63
336.69
963.36
6,666.99
9,999.66
3,333.99
3,366.99
6,699.33
9,966.33
9,636.69
3,696.36
6,963.99
6,699.33
66,699.33
99,966.66
33,366.33
36,963.36
69,636.36
33,333.66
66,666.99
99,999.33
96,369.63
36,963.36
68.97
603.30
6,366.33
67,029.66
639,965.01
Performing subtraction using all number keys
Decimal Selector—F
456.73
2123.21
789.01
2456.00
741.00
2258.10
852.55
2369.88
987.98
2102.55
333.52
333.01
482.90
482.67
885.43
Using a Calculator and Computer Keypad
Appendix C
C-5
DRILL C-6
DRILL C-7
Performing multiplication using all number keys
Decimal Selector—F
654.05
3 12.66
975.01
3 27.19
487.10
3 30.21
123.56
3 50.09
803.75
3 1.45
8,280.273
26,510.5219
14,715.291
6,189.1204
1,165.4375
Performing division using all number keys
Decimal Selector—F
900.56
500.25
135.66
269.155
985.66
4
4
4
4
4
450.28
100.05
6.65
105.55
22.66
5
5
5
5
5
2.
5.
20.4
2.550023685*
43.49779346*
*Number of decimal places may vary, due to machine capacity.
C-6
Appendix C
Using a Calculator and Computer Keypad