TI-83 Tutorial
BASIC COMPUTATIONS
The add [+], subtract [−], multiply [×], and divide [÷] buttons are blue. When pressing the
[×] button, the screen prints *. Also, when pressing the [÷] button, the screen prints /.
Example 1: Compute 8 − (5)(3)
Just type the whole formula directly into the calculator. It knows order of operations.
Then press the [ENTER] button.
Here is the key sequence:
[8] [−] [5] [×] [3] [ENTER]
The screen should look like this
Notice that computations are shown on the left side of the screen, and answers are shown
on the right side of the screen. Also, press the [ENTER] button anytime you want the
calculator to do the compuations you entered.
SQUARING
Use the [x2] button for squaring.
Example 1: Calculate 3(4)2
Here is the key sequence:
[3] [×] [4] [x2] [ENTER]
The screen should look like this
Notice that new computations are printed below the previous ones. This way, you can
refer to previous calculations if necessary.
CLEARING THE SCREEN
Press the [CLEAR] button to clear the screen. All subsequent examples will start with a
cleared screen.
NEGATIVE NUMBERS
To enter negative numbers, use the [(−)] key. It’s just to the left of the [ENTER] key.
Press the [( −)] key before the number. Be sure not to confuse this with the minus button.
Example 3: Compute (-4) + (-2)
Here is the key sequence:
[(−)] [4] [+] [(−)] [2]
The screen should look like this:
PARENTHESES
Use the [(] and [)] keys when computations involve parentheses.
Example 4: Compute 8 − (5 + 4 × 2)
[8] [−] [(] [5] [+] [4] [×] [2] [)] [ENTER]
Use parentheses for the division bar as well.
32 + 8
Example 5: Compute
4 −1
Recall that, when working with a division bar, do all the computations on the top, then do
all the computations on the bottom, then divide. Since there is no “division bar” button on
the calculator, use parentheses to tell the calculator to add 32 + 8 first, then subtract 4 − 1,
before dividing.
[(] [3] [x2] [+] [8] [)] [÷] [(] [4] [−] [1] [)] [ENTER]
CAUTION: if you forget the parentheses, you will get the incorrect answer:
The reason is the calculator always follows order of operations. It will always add and
subtract last, unless there are parentheses to tell it otherwise. To the calculator, the entry
32 + 8/4 − 1 means
32 +
8
−1
4
[ 2nd ] BUTTON
Use this button to access all the yellow writing. For example, the square root sign is in
yellow, above the [x2] button.
SQUARE ROOT
Press [2nd] then press [x2] to access the square root. When you do this, the screen will
also print an opening parentheses. Like this:
So be sure to include closing parentheses at the end.
Example 6: Compute
7+3
[2nd] [x2] [7] [+] [3] [)] [ENTER]
EXPONENTS
Use the [^] key for exponents
Example 7: Compute (1.6)8
[1] [.] [6] [^] [8] [ENTER]
The screen should look like this:
[ANS] BUTTON
The letters ANS are written in yellow, above the negative [(−)] button. This is short for
“answer”. It is used to recall the last computed answer in the calculator.
Example 8: Suppose you wanted to subtract the answer in the previous example from 50.
In other words,
Compute 50 - (1.6)8
Instead of typing the whole expression again, use ANS
[5] [0] [−] [2nd] [(-)] [ENTER]
The calculator computed 50 − 42.94967296 = 7.05032704. The number, 42.94967296,
was the result of the previous calculation.
Example 9: Suppose you wanted to take the previous result and multiply it by 2. You
don’t have to re-type the last number, or even press the [ANS] button. Just press:
[×] [2] [ENTER]
The calculator automatically will print Ans for you.
[X, T, θ, n] BUTTON
Sometimes you will need to use the variable x in your computations. Pressing this button
will print an x on the screen. If you’re curious why there is also a T, θ, and an n on this
button, these are used for more advanced mathematics. We’ll just ignore these and use
the x for now.
[STO→] BUTTON
This is the “store” button. Use this if you want to the calculator to remember a number.
Example 10: Suppose you want to save the number 14.10065408 from the last example.
[STO→] [X, T, θ, n]
Now, any time you press the [X, T, θ, n] button, the same number, 14.10065408, will
appear.
[ALPHA] BUTTON
You can type other letters besides X. All the letters of the alphabet are written in green
letters on the calculator (in alphabetical order)
Example 11: Type the letter P on the calculator.
The letter P is above the [8]. So press:
[ALPHA] [8]
The calculator considers the letter P to be a variable. So if no number has been stored in
the variable P, it will return 0 for an answer.
You can use any letter as a variable.
Example 12: Let p = -9 and q = 7.8. Compute –8p3 + q
You could just replace p with –9 and q with 7.8 on paper, then do the computations:
-8(-9)3 + 7.8
However, here is an alternative method:
Store the numbers into the variables P and Q on the calculator:
[(−)] [9] [STO→] [ALPHA] [8] [ENTER]
[7] [.] [8] [STO→] [ALPHA] [9] [ENTER]
Then type the formula –8p3 + q. When the calculator sees the P, it will replace it with a –
9, and when it sees Q, it will replace it with 7.8:
[(−)] [8] [ALPHA] [8] [^] [3] [+] [ALPHA] [9] [ENTER]
Notice that it is not necessary to put a multiplication symbol between the –8 and the P. If
a number is put next to a letter on the calculator, it automatically knows to multiply.
[MATH] BUTTON
The [MATH] button accesses miscellaneous mathematic commands, such as absolute
value, cube root, etc. All these commands are organized into four categories:
1) Math commands. These are various mathematical commands, such as cube root.
2) Number commands (abbreviated as NUM). These commands are applied to numbers,
such as absolute value and rounding.
3) Complex number commands (abbreviated as CPX). These commands are used with
imaginary numbers.
4) Probability commands (abbreviated as PRB). These commands are used in the field of
probability.
When you press the [MATH] button, you see a menu of options:
Across the top you see the four categories (MATH, NUM, CPX, and PRB). To move
from category to category, use the left arrow [◄] and the right arrow [►]. To move up
and down the menu, use the up arrow [▲] and down arrow [▼].
Example 13: Compute
3
75
The cube-root command is the 4th command under the MATH category. After pressing
the [MATH] button, move the arrow down until you reach the cube-root command. Press
[ENTER] to select the command. Then type 75 and closing parentheses. The entire key
sequence is below:
[MATH] [▼] [▼] [▼] [ENTER] [7] [5] [)] [ENTER]
Alternatively, you can also just press the number of the selection instead of using the
arrow keys. For instance, the above example could have been solved with the following
key strokes:
[MATH] [4] [7] [5] [)] [ENTER]
Example 14: What is the least common multiple of 120 and 345?
This can be solved by the lcm command, which is option #8 under the NUM category.
Press the [MATH] button, then use the right arrow key [►] to move to the NUM
category. Then move the down arrow key to option #8:
[MATH] [►] [▼] [▼] [▼] [▼] [▼] [▼] [▼]
Then press [ENTER] to select this command. (or just press 8).
Now the screen will look like this:
Then type 120, 345 and closing parentheses, then press enter:
The entire key sequence is:
[MATH] [►] [▼] [▼] [▼] [▼] [▼] [▼] [▼] [ENTER] [1] [2] [0] [,] [3] [4]
[5] [)] [ENTER]
GRAPHING
The blue buttons on the top row of the calculator are used for graphing. Here is a brief
explanation of each one:
[Y=] Press this button to begin entering the equations you want to graph
[WINDOW] Press this button to adjust the viewing screen
[ZOOM] This button allows you to “zoom in” for a closer look or “zoom out” for a
larger picture.
[TRACE] This button lets you move a cursor up and down the curve or line that has been
graphed.
[GRAPH] Press this button to look at the graph.
Example 15: Graph y = 0.4x2 − 2x
Press the [Y=] button. Then you will see the following screen:
Use this screen to enter equations you want graphed. Where it says Y1, type the equation
0.4x2 − 2x. Use the [X, T, θ, n] button for x.
Here is the key sequence:
[0] [.] [4] [X, T, θ, n] [x2] [−] [2] [X, T, θ, n] [ENTER]
Next, press the [GRAPH] button, and you will see the picture of the graph:
This is the “standard” viewing window. The x-axis goes from –10 to 10, and the y-axis
goes from –10 to 10. Each tic-mark represents one unit. If your calculator does not show
the same graph as above, it is probably because the calculator had another setting. In this
case, press [ZOOM], then select option #6, which is ZStandard. This will give you the
standard setting.
[ZOOM] BUTTON
Example 16: Suppose you wanted to look at the “big picture” instead of only from –10 to
10. You can “Zoom out”.
Press the [ZOOM] key. Select option #3, which is Zoom Out, then press [ENTER].
The calculator will show the original graph. Press [ENTER] again. The calculator will
now redraw the graph.
After zooming out once, the x and y axes go from –40 to 40. If you’d like, repeat this
process to zoom out even further.
Example 17: Zoom in to take a closer look at the vertex (the turning point of this curve).
Press the [ZOOM] key. Select option #2, which is Zoom In.
Press [ENTER] to select it. The calculator does not zoom in automatically. First, use the
arrow keys to move the cursor (the cursor looks like a small + sign) to the area you want
to zoom in to. In this case, move the cursor to the vertex.
Move the cursor
to this location.
Notice that, as you begin to move the cursor, the bottom of the screen shows the x and y
coordinates of the cursor. Once you have moved the cursor to the desired location, then
press [ENTER].
Next, press [ENTER] again to zoom in further:
You can continue to zoom in to see as much detail as you would like.
USING THE TABLE
In addition to graphing a function, the calculator can also generate a table. Above the
[GRAPH] button, notice the word “TABLE” written in yellow letters. This is used when
you want a table of x’s and y’s instead of a graph.
Example 18: Make a table of y = 2x +
3
x+2
First, press [ Y= ]
Then enter the function. Press [ 2 ] [ X, T, θ, n ] [ + ] [MATH] [▼] [▼] [▼]
[ENTER] [ X, T, θ, n ] [ + ] [ 2 ] [ ) ] [ENTER]
Now, instead of pressing the [GRAPH] button, press [ 2nd ] [GRAPH]. You will see a
table of x-coordinates along with the corresponding y-coordinates.
Example 19: When x = -5, what is y?
There are two ways to find the answer. First, just do the calculation: 2(-5) + 3 −3 + 2
But, since we just entered this formula into the calculator, just use the table. Use the [▲]
button to "scroll up" until we find -5 for x:
Answer: When x = -5, y = -11.44
TABLE SET-UP
Above the [WINDOW] key, you will see TBLSET written in yellow letters. This is short
for TABLE SETUP. This is used when you want other x-values for the table.
Example 20: Make a table for the function y = 2x + 3 x + 2 . Start with x = 2, and
increase the x-value by 0.25. In other words, complete the table:
x
y
2
2.25
2.5
2.75
3
3.25
3.5
3.75
4
4.25
This is the same equation from the previous example. So, the equation should already be
entered. If not, see the last example to see how to enter the it.
Press [ 2nd ] [WINDOW] to access the Table Setup.
This window shows the options available for setting up the table. We are interested in the
first two options, TblStart and ∆Tbl.
TblStart is short for Table Start, which tells you what is the first x coordinate on the
table. In this example, we want the table to start at 2
∆Tbl means “Change in table” (in mathematics, the delta ∆ symbol usually means
change). This allows you to adjust the aamount of the increase of the x-coordinate on the
table. In this example, we to increase by 0.25.
So, press [ 2 ] [ENTER] [ 0 ] [ . ] [ 2 ] [ 5 ] [ENTER]
Then, press [ 2nd ] [GRAPH] to look at the table.
Notice that x starts at 2, and increases by 0.25. Just like we told it to.
MORE ABOUT TABLE SETUP
Sometimes you just want to know the values for y for just a few values of x. In this case,
you can change an option in TABLE SETUP so that you can enter any value you want
for x.
Example 21: Using the equation y = 2x +
3
x + 2 , if x = 2.345, what is the value of y?
This is the equation from the previous examples, so it should still be stored in your
calculator. Press [ 2nd ] [WINDOW] to access the Table Setup:
The third line under TABLE SETUP says Indpnt:, which is short for Independent
Variable. (the independent variable is x.) By default, it is set to Auto, which means the
calculator automatically enters values for x into the table. Use the arrow keys to select
Ask. Then press enter:
If the cursor is currently at the top of the screen, you will press
[▼] [▼] [►] [ENTER]
Then, if you press [2nd] [GRAPH] , the table will be blank, because the calculator is
waiting for you to enter a value for x.
The cursor should be at the bottom of the screen. Type 2.345, then press [ENTER]. The
calculator will now compute the value for y.
SETTING THE WINDOW
The [WINDOW] button lets you set the x-axis and y-axis of a graph yourself. This
sometimes easier than the [ZOOM] button.
Example 22: Graph y = 2x3-140x2-10x+12000, from x = -20 to x = 100
A graph (not using a graphing calculator) of the equation looks like this:
150000
100000
50000
-20
20
40
60
80
100
-50000
On the graph above, the x-coordinates ranges from -20 to 100, and the y-coordinates
ranges from about -100,000 to 150,000. If this were graphed on the standard window of a
TI-83, you won’t see anything. You would have to zoom out many times so you could
see the graph above. Luckily, there is a way to adjust the x and y coordinates so we can
see very large (or very small) coordinates.
First, press [Y=] and enter the equation into the calculator:
Next, press [WINDOW]
By default, the coordinates on a graph range from -10 to 10. But this time we want the xcoordinates to range from -20 to 100. So, set XMin (short for x minimum) to -20, and
XMax (short for x maximum) to 100.
As you can see, the x-coordinates range from -20 to 100, and the 11450 (when x = -5) to
12234 (when x = 9). So we will set the -coordinates range from 11450 to 12048. So we
will set the y-axis from 11400 to 12300. (It doesn’t matter exactly what to set the y-axis
to, just as long as it includes the highest and lowest y-values.) Also, we will set the x-axis
from -5 to 9
Press [WINDOW], and you will see a list of options. (by the way, we will skip over the
Xscl option)
Enter the settings into the calculator:
[ (-) ] [ 5 ] [ENTER] [ 9 ] [ENTER] [ENTER] [ 1 ] [ 1 ] [ 4 ] [ 0 ] [ 0 ] [ENTER] [
1 ] [ 2 ] [ 3 ] [ 0 ] [ 0 ] [ENTER]
Then press [GRAPH] to see the graph.
QUIT KEY
Above the [MODE] key, you will see the word QUIT written in yellow letters. This takes
you back to the “Home” screen, where you do basic calculations. Just press
[ 2nd ] [MODE]
ENTRY KEY
This is a very handy feature. Above the [ENTER] button, you will see the word ENTRY
written in yellow letters. This prints the last entry from the calculator.
Here is an example of how it works. Enter the calculation 4 + 62
[ 4 ] [ + ] [ 6 ] [ x2 ] [ENTER]
Now suppose you made a mistake, and you should have entered 4 + 52 instead.
Rather than typing the whole formula again, just press
[ 2nd ] [ENTER]
And the last entry appears. Use the arrow keys to go back to the 6, and type a 5.
[◄] [◄] [ 5 ] [ENTER]
Notice that the calculator types over the old number, rather than inserting the number. If
you want to insert a number, keep reading!
DELETE KEY
The [DEL] key (short for delete) has the same function as the delete key on a PC
computer keyboard. Here is an example. Enter the calculation 80 – 60, but don’t press
enter. Suppose you change your mind and you only want to enter 80. Use the arrow keys
to move the cursor to the minus sign, then press the delete key 3 times.
INSERT KEY
The INS command (short for insert) is in yellow letters above the [DEL] key. Use this to
insert a number, letter, or symbol into something that has already been typed, without
erasing anything. For example, type 2 + 8
[2nd] [ x2 ] [2] [+] [8] [ ) ] [ENTER]
Now suppose you changed your mind and wanted to compute
20 + 8
Press [2nd] [ENTER] to bring back the previous entry. Move the cursor to the + sign.
Then insert the 0:
[◄] [◄] [◄] [2nd] [DEL] [0]
Notice that the cursor changes from █ to __ when the calculator is in “insert” mode.
SCIENTIFIC NOTATION
__________
,
EE (written in yellow letters above the [ ] button) is used to enter numbers in scientific
notation.
Example 21: Enter 5.092 * 10-8 into the calculator.
Here is the key sequence:
,
[5] [.] [0] [9] [2] [2nd] [ ] [(-)] [8] [ENTER]
If the number is “too big”, the calculator will give the answer in scientific notation.
Example 22: Compute 6,000,000 * 450,000
RESETING THE CALCULATOR
If your calculator acts strange (this can happen if you accidentally set the calculator to a
different mode, or if you borrowed the calculator) and you can’t figure out how to fix it,
you can reset the calculator to the factory settings. However, this erases all stored
numbers, programs, etc., so use this cautiously.
Above the [+] button you will see MEM (short for memory) in yellow letters. This
activates the MEMORY menu. Select option 7 (Reset…)
Then you will see another menu. Select option 1 (All RAM…)
As a precaution, the calculator asks if you really want to do this. If you are still willing to
reset the calculator, select option 2 (Reset).
The last screen says all the RAM is cleared. By the way, RAM stands for random access
memory.