Radio Shack EC-235 Owner's Manual
OWNER’S MANUAL — Please read before using this equipment.
©
2000 RadioShack Corporation.
All Rights Reserved.
RadioShack and RadioShack.com are trademarks used by RadioShack Corporation.
EC-235 8-Digit Pocket Calculator
Your RadioShack EC-235 8-Digit Pocket Calculator’s compact size
lets you use it almost anywhere.
Percentage Key — simplifies discount, percentage, and tax calcula-
tions.
Square Root Key — quickly computes the square root of the dis-
played number.
Constant Calculations — let you add, subtract, divide, or multiply the
same number over and over without having to re-enter that number.
Large 8-Digit Liquid Crystal Display — makes it easy to read calcu-
lation results.
Protective Wallet — protects the calculator’s keypad.
OPERATION
You can enter basic, mixed, percentage,
add-on, and discount calculations.
Press
ON/C
to turn on your calculator.
If you do not press a key for about 8 minutes,
your calculator automatically turns off. To
turn it off sooner, press
OFF
.
Correcting Entry Errors
If you enter an incorrect value, press
CE
(Clear Entry)
once. Then enter the correct
value and continue your calculation.
To clear the display for a new calculation,
press
ON/C
(On/Clear) so
31
31
31
31
appears (this also clears the calculator’s
memory). Then begin the new calculation.
If you press an incorrect operator key (
++++
,
–
,
××××
,
÷÷÷÷
), simply press the cor-
rect key and continue your calculation.
Constant Calculations
For addition, subtraction, and division, the value you enter before
pressing
====
is the constant. For multiplication, the value you enter be-
fore pressing
××××
is the constant.
Exponential, Square Root,
and Reciprocal Calculations
Memory Calculations
To store a value in memory, first clear the memory and the display by
pressing
(Memory Recall/Clear) twice, then press
CE
.
To add a value to memory, enter the number or calculation you want to
add, then press
M
++++
. The calculator totals the current calculation (if one
is pending) and adds that value to memory.
To subtract a value from memory, enter the number or calculation you
want to subtract, then press
M–
. The calculator totals the current calcu-
lation (if one is pending) and subtracts that value from memory.
To recall the value from memory, press
once.
Calculation Errors
(5525
(5525
(5525
(5525
appears when:
• A calculation result exceeds 8 digits. This is an overflow error (see
“Estimating Calculation Results” ).
• A memory calculation result exceeds 8 digits to the left of the dec-
imal point. The memory contents remain unchanged.
• You try to divide by 0.
• You try to calculate the square root of a negative number.
If
(5525
(5525
(5525
(5525
appears, press
ON/C
to clear the error.
Estimating Calculation Results
If you perform an operation that results in an overflow error, you can
estimate the correct result (to 8 significant digits) by following these
steps.
1. Count the number of digits to the left of the decimal point.
2. Remove the decimal point.
3. Add as many zeros to the right of the number as there were digits
to the left of the decimal point.
For example, if
(5525
(5525
(5525
(5525####413475397
413475397
413475397
413475397
appears, the approximate answer is
101,420,640. If
(5525
(5525
(5525
(5525#### 64<1:367:
64<1:367:
64<1:367:
64<1:367:
appears, the approximate answer is
31,970,347,000.
Calculation
You Press
You See
7 + 3
====
10
5 + 3
====
8
7 + 3
====
5
====
431
431
431
431
;1
;1
;1
;1
260
×
12.3
====
3198
260
×
4.15
====
260
××××
12.3
====
4.15
====
64<;1
64<;1
64<;1
64<;1
43:<1
43:<1
43:<1
43:<1
Calculation
You Press
You See
2
3
= 8
2
××××
= =
;1
;1
;1
;1
The square root of 2 is 1.4142135
2
417475468
417475468
417475468
417475468
1
/
8
= 0.125
8
÷
÷
÷
÷
=
31458
31458
31458
31458
M
R
C
M
R
C