Casio Fx82LB Manual

							16  Mastering the calculator using the Casiofx-82LB
Or you can use your calculator to add fractions. Find the
 key
On the  key the ‘a’ represents the whole part of a mixed 
number and the ‘’ represents the fraction part of a mixed number.
When the number you are typing is a proper or improper fraction the ‘a’ is zero and there is no 
need to type a value for it.
The key strokes required for the calculation  are:
and the display will show 37 ⎦ 252 which is read as 
ab
c ---
fraction key
ab
c ---
b
c ---
1
1
2------4
63------+
37
2
52 --------- 
						

							Mastering the calculator using the Casiofx-82LB  17
Example
Find 
Using the calculator the key strokes are:
and the display will show 8 ⎦ 71 ⎦ 72 which is read as 
Note if you now press  the display will read . So this key turns a mixed 
fraction into an improper fraction.
If you press the  key a second time the decimal equivalent is displayed,  
i.e. 8.9861111
Example
Find 
(This means the square root of 25 cubed).
The calculator strokes are:
The display should read 125.
7. Scientific notation
Sometimes you may have numbers expressed in scientific notation, i.e., 7.24 × 103 instead of 
7240. When a number is multiplied by 10
3, you move the decimal point three places to the 
right. You can do this on the calculator by using the 
key.
819 ---
63
72------+
87172------
647
72 ---------
25
3
2 --- 
						

							18  Mastering the calculator using the Casiofx-82LB
Press , the screen shows 7240.
Example
If you want to multiply two numbers e.g. 8.34 × 10–2 × 4.28 × 105. Press
and the display will read 35695.2
If you want this answer in scientific notation press . The screen shows
The  puts it into scientific notation and the  gives you 10 digits on the screen.
If you press  the display will read 3.57004. This means 3.570 × 1004. This 
rounds the number to 4 digits. 
Practise using the  and  keys on your calculator  
						

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8. Using the 1/x key
This is a very useful key in more complex calculations. Find the  key on your 
calculator. It is above the  key.
Example
Look at this example
 is the same as  or 
You can input this in your calculator by pressing
The answer should be 0.571428571. This would be the same as if you just typed 4 ÷ 7
Use thekey to
activate 1/x
4
7 ---41
7 ---×1
7 --
-4× 
						

							20  Mastering the calculator using the Casiofx-82LB
Take another example
Ty p e :
The answer should be 0.051948051
9. Factorial x!
Look at your calculator and find the key with the symbol x! on it. You will come across this 
symbol when doing the Binomial Distribution. This is called the factorial key.
Use it to find the 3! and 5!. Press 
3! means 3 × 2 × 1  and 5! = 5 × 4 × 3 × 2 × 1
3! = 6 5! = 120
4
83+ ()7×--------------------------
Use the shift key 
to activate x! 
						

							Mastering the calculator using the Casiofx-82LB  21
How many ways would you guess that we could arrange ten people?
That is, how large would you estimate 10! to be? Use your calculator to find 10!
You should get 3 628 800.
10! = 10 × 9 × 8 × ... × 3 × 2 × 1
(Thank goodness this can be done on the calculator.)
10. Using memory
To calculate the following it may be useful to use the memory key for each term:
Example:
To make sure memory is clear, first press
and make sure you are in normal calculation mode [may need to press mode 1].
A small M appears in the display when you put something in memory.
916– ()2
16----------------------23 16– ()
2
16 -------------------------17 16– ()
2
16 -------------------------++
these keys are for memory
key to activate M-) (Use the 
						

							22  Mastering the calculator using the Casiofx-82LB
To do the calculation above, press the following keys
- this puts the first term (3.0625) into the memory
then press
- this adds the second term (3.0625) into memory
then press
- this adds the third term 0.0625 to memory.
To find the answer press 
The answer should be 6.1875.
Example 2
calculate the following:
first  to clear the memory then
press the following keys:
your answer should be 11.39917438
18
17----------17
17 ----------
12
17----------++ 
						

							Mastering the calculator using the Casiofx-82LB  23
11. Statistics
11.1 Mean and standard deviation – single data
The formula for the mean is 
The formulas for the sample standard deviation are
(Theoretical formula)
(Working formula)
Your calculator will calculate the mean and standard deviation for you (the population 
standard deviation 
 or the sample standard deviation  or s – in data calculations you 
will usually use the sample standard deviation.)
The differentiation between σ and s varies with different calculators. On the Casio fx-82, σ is 
denoted by σ
n and s is denoted by . The positions of these keys is shown on the diagram 
below.
xΣx
n------=
sΣxix – ()2
n1 – ------------------------=
sΣxi2Σxi()2n⁄ –
n1 – ---------------------------------------=
σnn-1
σn-1
input data key(key for population 
standard deviation)
(key for mean)(key for sample 
standard deviation) 
						

							24  Mastering the calculator using the Casiofx-82LB
To find the mean and standard deviation,
firstly you must access the statistics mode of the calculator by using the keys  followed 
by  SD will appear in the screen.
Note that once you are in the statistics mode, the keys shown within the blue lines are active. 
There are 9 blue keys on the Casio fx-82. Make sure you can locate them. Before starting any 
computations always clear the statistic’s memories using SAC. Press 
I will use the data set A (–5, 2, 3, 4, 11) to demonstrate the use of the calculator. Note that I 
have shown the use of the 
 key where necessary.
Step 1: Input the observations.
Use the  key to input data (no need to press ).
Step 2: Check that the correct number of observations have been inputted.
Press 
The display should read 5.
Step 3: Display the mean
 and the display should read 3
Step 4: Display the standard deviation (assume the data set is a sample)
 and the display should read 5.7008771
__________________________________________________________________________ 
						

							Mastering the calculator using the Casiofx-82LB  25
Example
Use your calculator to find the mean, standard deviation and variance for data set B: –18, 1, 3, 
9, 20.
(the variance is the square of the standard deviation)
__________________________________________________________________________
After you are in the statistics mode, cleared the statistics memories and input the data, the 
keystrokes required are:
 and the display will read 5
 and the display will read 3
 and the display will read 13.87443693
 and the display will read 192.5
The mean is 3, the standard deviation is 13.87 and the variance is 192.5.
The  button accesses a number of extra statistical functions. 
 = Σx2 = Σx
In the example below, the progressive calculations are shown simply to give you some 
understanding of the underlying processes – you should do one or two examples in detail and 
then check them by calculator.
Note: This calculator will not perform bi-variate calculations.