Unofficial Casio fx-82LB Fraction Calculator Manual

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This manual is not the offical manual from Casio. Actually, I lost my manual a long time ago. One day, I needed to do some calculations, but I forgot how to use it! Then I spent an afternoon to figure out how to use it, and wrote this manual. So if I forget the usage again, I won't waste another afternoon.

Hardware Maintainance

Casio fx-82LB Fraction uses two AA size batteries. AA size is very common, and that is the reason I choose to use this model. I don't want to bother to search for some special button-shaped batteries. Another reason: AA size batteries are much more cheapter than the button batteries.

To replace the batteries: unscrew the four back screws, uncover the back cover. The two AA size batteries are very accessible.

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Basic Arithmatic Operations

+, -, × and ÷ operations are too trivial to be described here.

Square operation: first, enter the number, followed by the × and = keys.

Constant calculations: press the +, -, ×, and ÷ twice can make the inputted operand a constant, and a k will display on the screen.

Unlike other operations, for the constant ÷ operation, constant is the dividor (second operand), not the dividant (first operand).

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Scientific and Engineering Functions

Notice: all the keys except the numbers are presented by black mono-width font.
Function Procedures
x2 input the operand, followed by the shift key, then the x2/sqrt key.
sqrt of x input the operand, followed by the x2/sqrt key.
10x input the operand, followed by shift, then 10x/log key.
log10x input the operand, then 10x/log key.

Note: for logxy, there is a formula:

logxy=(logwy)/(logwx)

ex input the operand, then shift, followed by ex/ln key.
Convert a(b/c) to decimal first, input a, followed by (d/c)/[a(b/c)], then b, (d/c)/[a(b/c)], c, (d/c)/[a(b/c)], = key, and (d/c)/[a(b/c)]
Convert a decimal to (d/c) or a(b/c) form input the operand, then (d/c)/[a(b/c)]. To furthur convert to a(b/c) form, press the = key.

Note : after the = key, the (d/c)/[a(b/c)] key toggles the decimal and a(b/c) form.

Convert degree/minute/second form to decimal, for example, 12°32'56" First, input the degree, then the [° ' "] key, then, the minute, followed by [° ' "], then, second, followed by [° ' "].

For the 12°32'56" example, first, input 12, [° ' "]; 32, [° ' "]; 56, [° ' "]. The output display is the result: 12.548889

Convert decimal to degree/minute/second form input the operand, followed by shift, then, the [° ' "] key.
sin(x) input the operand, then, followed by sin-1/sin key.

Note: the format of the operand can be degree(DEG), radian(RAD), and gradiant(GRA). The convertion formula is: 2*pi=360°=400GRA.

To switch among DEG, RAD, and GRA:
press the mode key, then:
for DEG, press 4
for RAD, press 5
for GRA, press 6

sin-1(x) input the operand, then the shift key, followed by the sin-1/sin key.
cos(x), cos-1(x), tan(x), and tan-1(x) Similar to sin(x) and sin-1(x)
sinh(x)

and cosh(x), and tanh(x)

 input the operand, hyp, then sin-1/sin.

Note: the cosh(x), tanh(x) operations are similar.
sinh-1(x)

and cosh-1(x), tanh-1(x)

 input the operand, shift, hyp, then sin-1/sin.

Note: the cosh-1(x), tanh-1(x) operations are similar.

Note: shiftand hyp keys can change positions with each other.

cubic root of x input the operand, then the shift key, then, the [cubic root/(+/-)] key.
shift decimal point by 3 to the right

for example, 5.638742 ×106 to 5638.742×103 to 5,638,742

press the ENG key.
shift decimal point by 3 to the left press the shift key, then the ENG key.
parentheses (X<->Y)/[(... and (X<->M)/...)]

Note: the maximum level of nesting is 6.

1/x input the operand, followed by shift, then, by the (1/x)/Min key.
x! input the operand, then the shift key, then the x!/MR key.
Convert polar coordinate to Cartesian (rectangular) coordinate:
(r, theta) to (x, y) 		input r, the shift key, the (P->R)/- key, theta, the = key, now you get the x value. Then, the shift key, the (X<->Y)/[(... key, you get the y.
Convert rectangular (Cartesian) coordinate to polar coordinate
(x, y) to (r, theta) 		input x, then the shift key, the (R->P)/+ key, input y, then = key, you will get r now. then, shift key, the (X<->Y)/[(... key, you will get theta now.
xy input the operand x, then shift, then the xy/× key, then input y, followed by the = key.
x1/y input x, shift, then, the x1/y/÷ key, input y, then = key.
input x * 10^y input x, then the pi/EXP key, then input y
Recall the value of pi shift, then pi/EXP.
Generate a random number in (0, 1) shift, then RAN#/.
round off the number in scientific notation mode and fixed number mode the RND/0 key.

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Statistical Functions

First, press mode key and RAN#/. to enter the statistical mode.

Suppose you have the following list of numbers to be analyzed:

56, 72, 39, 43, 67, 54, 38, 74, 34, 53.

input the number, followed by the × key, then the next number, until the end of the list of numbers.

Check the number of samples: press the shift key, followed by the n key. The result should be your sample size. Here, the sample size is 10. For the other statistical operations, see the following table.

operation procedure
average shift, x bar. In this case, the result is 53.
sum of squares shift, sum of squares, here the result is 29980.
sum shift, sum, here the result is 530.
standard deviation to n and to (n-1) similar procedures.
delete all numbers shift, then SAC. SAC means Statistical All Clear, Statistical AC.
delete a number from the list input the number, followed by the shift key, then press the DEL key.

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Modes of the Casio fx-82LB Fraction calculator

First, press the mode key. Then, press one of the following keys for corresponding modes.
key modes
. statistical mode
0 change from statistical mode back to the normal computing mode.
4 DEG, use degrees to measure angles.
5 RAD, use radian to measure angles.
6 GRAD, use gradiant to measure angles.
7 and #(a number) Fixed number format. # is the decimal point position.
8 and #(a number) Scientific notation. # is the decimal point position.
9 Change from fixed mode or scientific notation mode back to the normal mode.

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Conclusion

The Casio fx-82LB fraction is a very good calculator for general scientific and engineering use. However, it lacks the hex, octal, and binary functions. On the other hand, if you are a computer engineer, you already have had more powerful tools to do the job, right?

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