E-mail Webmaster


Recent Additions

Frank's Letters

English Section

Math Tutorials

TI Graphing Calculators
Mobile Phones & Pads

TI Program Descriptions

TI Programs
TI Programming Keystrokes

Python Programs

Brief User Guides

TI-82 User Manual
TI-83+ User Guide

TI-89 User Guide


TI-82 Statistics
TI-83 Plus Statistics
TI-84 Statistics
TI-89 Statistics

Other Topics
TI-83Plus Finite Math
TI-83 Plus Finance Math
TI-83 Plus Busines & Economics
TI-83 Plus Lin Prog
TI-83 Plus Geometry
TI-84 Conics APP
TI89 Calc Dif Eq
TI-89 Finance
Arithmetic of  Lists
TI-89t Busines & Economics


For Beginners
More Detailed Page 1
More Detailed Page 2
TI-89 FAQs

Links to  Guidebooks by TI
TI-83 Plus

Casio Graphing    Calculator

Casio Program Descriptions

Casio Programs
CFX-9850 & CFX-9750

Brief  Guides

CFX-9850 & CFX-9750
User Manual

Statistics Guide

Casio Programming Keystrokes
Brief Guides Other Calculators
HP 43S Calculator

Scientific Calculators
FAQs for Scientific Calculators


Sección Española

FAQs en Español
FAQs Basicos
Mas Dificil Pagina 1
Mas Dificil Pagina 2

Guías en Espaňol
TI-82 Espanol
TI-82 Estidisticas
TI-83 Plus Espanol
TI-83 Plus Estidisticas
TI-83 Plus Guía Financiera
TI-89 Titanium Guía
TI-89 Estidisticas
TI-89 Guía Financiera


Casio Calculadoras

Breve Guía Español
Cfx-9850 & Cfx-9750

Casio FAQs en Espanol

Calculadoras Científicos

FAQs en Espanol
Programs at Other Sites

Links to Tutorials



How to find an answer on this sheet: In order to make maintenance of this sheet easier, I designed it so that you can use your browser to find answers. After you've located the FAQ number that you want, just use the Find and enter the index number.  The start point for the search should be below the listing in the index.

(1)  What's the best scientific calculator to buy, and where's the best place to buy one?
(2)  How do you do fractions on a scientific calculator?
(3)  How do you do mixed numbers on a scientific calculator?
(4)  My calculator has second power and third power, but how do you raise to a higher power such as 6?
(5)  I know what the EXP on my calculator is, but what's the ENG for?
(6)  What's the x-1 on my calculator for?
(7)  How do I change base of logs on a calculator?
(8)  I often get the wrong answer when I enter an expression with several operations.  Why?
(9)  What's the reason for parentheses on my calculator?
(10)  How do I find what the angle whose cos is 0.5?
(11)  I see the letters AOS and EOS on calculator sheets.  What do they mean?
(12)  What are the parentheses for on a Casio Scientific calculator?
(13)  When I enter (-32)^(1/5); then (-2)^3 I get a correct answer, -8, but when I enter (-32)^(3/5) I get Ma    ERROR.  Why?
(14)  My brother gave me an expensive calculator,  HP-42S, without a book.  I can't even add on it.  Can you help? 
(15)  What does S-V.P.A.M. on the Casio scientific calculator s mean?
(16)  Will the Casio fx-7400G do fractions?

DISCLAIMER:  The FAQs on this web site, and especially particular FAQ #1 here,  reflect the writer's subjective opinion and observations. The FAQs should be considered only as another source of information.  The writer is not endorsing any particular brand or model of the calculators mentioned or any particular store or shop. The writer does not warrant the accuracy of any FAQ.  Any calculator mentioned may not be a representative sample of what is on the market, and the manufacturers may change their products or specifications without my knowing about it.

(1) What's the best scientific calculator to buy, and where's the best place to buy one.
I prefer not to make specific recommendations about manufacturers and vendors on this website, but I'll tell you what to look for and where you can find some good prices. 
        First of all, don't buy one of those six- or eight-function calculators that are little more than an adding machine.  Definitely do buy one with a two-line display, and I like very much algebraic entry. (That's called V-S.P.A. M and EOS in TIs.)   The two-line displays keep both your entry and your answer on the screen at the same time.  Make sure it has "Replay" or some such  provision for moving the cursor so that you can make corrections.  You'll also need an INS, insert, for entering things you may have left out in your entry.  Make sure it has a fraction function. That looks like this:
ab/c.  It should have provisions for entering powers of 10.  That would be something like EE or EXP.  It should also have these:  Trig functions, log, ex , ln, nPr, nCr, and x2, square root,  and provisions for taking roots and powers other than two (either xy or ^.).  Some students may want complex number capability.
     If you're attending an electronics technical school, you might look for a calculator with BIN, HEX, and OCT.  Some calculators have the logic functions AND, OR, and XOR.  Again these might be of some use to electronic technicians or those aspiring to be.  You can also evaluate a logic expression such as ~(p.~q).  But I've found that most teacher don't use a calculator for evaluating logic functions, and most students don't go to the trouble to learn how to use a calculator for that. 
 Where to buy:  I'm not going to tell you where to buy a calculator; I'm going to tell you some places they're available.  Wal-Mart, Best Buys, Office Depot, Office Max, Target (I believe Target still has them.), and others that may be specific to your area.  You can buy a scientific calculator that is  satisfactory for many people students can be had for a little less than ten dollars.   A Casio fx-300MS sells for $9.73.  A TI-30xIIs that is has a few more functions than the Casio mentioned,  sells for $14.96.  A Casio fx115MS sells for $14.66.  This calculator has all of the normal functions mentioned above as being necessary plus complex numbers and numerical integration and differentiation. These prices are as of 3/20/05. 
(2)  How do you do fractions on a scientific calculator?
      For most scientific calculator you use the
ab/c key.  Let's say you wanted to add 1/3 + 1/4; then the keystrokes would be these:  (Where the commas are for separation only and are not entered.)
ab/c, 3,+, 1,ab/c,4, =

(3)  How do you do mixed numbers on a scientific calculator?
      Read number 2 above and you can probably figure it out yourself.  Just put another
ab/c key stroke between the whole number and the fraction.  Say you wanted to add 4 1/3 + 3 1/4; then the keystrokes would be these.  4, ab/c, 1, ab/c, 3, +, 3, ab/c, 1, ab/c, 3, =.  Your answer would be 7  7/12.

(4)  My calculator has second power and third power, but how do you raise to a higher power such as 6?
The sequence of the keystrokes may vary with the calculator, but the basic method is to use either  the xy key or the ^symbol.  Let's say you want to raise 6 to the sixth power; then the keystrokes would be these:  6, xy , 6, =.  Note that if you press 2nd or SHIFT, depending on the calculator, you can also use that same key to do higher roots.  For those calculators that use the ^ symbol, the keystrokes would be 6^6=.

(5)  I know what the EXP on my calculator is, but what's the ENG for? That's for engineering units.  These are usually expressed in exponents that are multiples of 3.  For example if you had 30000 on your display and you pressed ENG, you'd get 30. 03.  Meaning 30 x 103 .  Similarly, .00001  would be displayed as 10. -06 .
(6)  What's the x-1 on my calculator for? 
That will give you the inverse of a number.  For example, 4, x-1 will give you 0.25.  On most scientific calculators you can convert that to a fraction, 1/4, by pressing
(7)  How do I change base of logs on a calculator?  Calculators only have two bases: log which is actually log10 and ln which is loge.   If you want to do a log to some other base, divide the log by the log of the base you want the answer in.  (If you're using ln; then divide the ln expression by the ln of the base.)  Example:  Find log7 12.   On your calculator enter this:  log 12/log 7.  If you're not sure if you did it right, you can always check it with these keystrokes:  <7>,<xy>,<Ans> if your calculator has an Ans key. 
(8)  I often get the wrong answer when I enter an expression with several operations.  Why?
You have to be careful to realize that the calculator will follow its order of operations unless you tell it to do otherwise with grouping symbols.
2x3+ 42
This must be entered as follows:
(2x3 +42)÷2
That'll give you 11.
If you enter 
2x3 +42÷2, then the calculator will first square 4 to get 16; then multiply 2x3; then divide 16 by 2 to get 8; then add 6 + 8 to get 14.
(9)  What's the reason for parentheses on my calculator?
Well, I don't want to be dogmatic and say what the reason is, but certainly an important reason is to give priority in the order of certain operations.  For example if we enter 16- 8÷4, we'll get 16-2 = 14.  If what we really wanted was to do the subtraction first, then we can do that by writing this: (16-8)÷4.  That'll give us 2.  Item 8, above, also deals with use of parentheses.
(10)  How do I find what the angle whose cos is 0.5?
First make sure that your calculator is set for radians or degrees, whichever you want the answer in. (Usually you'll want it in degrees.)  Most scientific calculators have the inverse trigonometric functions as a 2nd or SHIFT function of the regular function keys.  For example, to find cos-1 0.5, just press 2nd or SHIFT, whichever your calculator has;  press the COS button; then enter the argument 0.5 and press = or ENTER or whatever your calculator has for executing an operation.
(11)  I see the letters AOS and EOS on calculator sheets.  What do they mean?
AOS stands for Algebraic Operating System, meaning that it does the arithmetic using the order of operations.  EOS stands for Equation Operating System, meaning that you make the entries just as you would write them in an equation.
(12)  What are the parentheses for on a Casio Scientific calculator?
Generally, parentheses on scientific calculators are used to change the order of operations or to clarify the order of operations.  All calculators do not respond in exactly in the same way, but these examples will give you some ideas about when you should consider parentheses.  My advice to students is, when in doubt, use parentheses.  .
Ex 1: 3*5+3 = 18, but 3*(5+3) = 24
Ex 2: 20 + 4 + 8/2 = 28, but 20 + (4+8)/2 = 26
Ex 3: e 2 + 3 = 10.389, but e(2+3) = 148.41
Ex 4: log 100 + 3 = 5, but log ( 100 +3) = 2.01
Ex 5: log 100 + 10² = 102, but log (100 + 10)² = 4.08
Be careful of this last one. On some calculators, for example the TI-83 Plus, the expression log (100 + 10)² is treated as squaring the result of the operation. You'll get 4.16 for an answer. To square only the argument on that calculator, you'll need to enter this: log ((100 + 10)²). When you're uncertain, the safe thing to do is to try a simple problem and see if you get the right answer.
(13)  When I enter (-32)^(1/5); then (-2)^3 I get a correct answer, -8, but when I enter (-32)^(3/5) I get Ma    ERROR.  Why?
It's probably because of the algorithm used in the last case.  Evaluating negative numbers with fractional exponents is a rather subtle issue, but the subtleties arise out of some decisions about efficiency or cost that engineers have make in the design or implementation.  Your problem arises because early designers of calculators chose to take advantage of the good algorithms for natural logs that they already had and apply those  to fractional exponents.  Here's how it went:
Solve the following:
y = x(3/5)
ln y = ln x(3/5)
ln y = (3/5)ln(x)
y = e((3/5)ln(x))
Then they can use the log algorithm that they already have implemented in hardware (originally) or software (later).
But it's clear that the last equation does not have the same domain as the first one.  The last equation becomes imaginary when "x"  is negative. The first one only becomes imaginary when x is negative and the numerator is odd and the denominator is even. 
Most scientific calculators, the TI-82 and the CFX-9850, do  x^m/n  using that logarithmic algorithm.  Some of these calculators call that problem a math error, others a domain error.  The TI-83 Plus will handle that expression okay.  However, it has another subtlety:  Some  people  think  (-1)2/2  should be +1, but the TI-83 Plus evaluates it as -1.  That comes about when you consider (
√-1)2 .  That just removes the square root and leaves -1.  I happen to agree with the way TI does it, but I've done probably more than enough hand waving and I won't go into that. 
(14)  My brother gave me an expensive calculator,  HP-42S, without a book.  I can't even add on it.  Can you help? 
As it happens, a student of mine had an HP-42S and I spent a few minutes figuring out how to use it so I could help her.  So, I'll can give you some help with the basics, but, sorry, I didn't get into the programming.
First of all, let's look at some of the functional keys.
1)  Red key:   The red key is pressed to shift  the function of an entry key to the red function printed on the panel above an entry key.
2)  Menus:  Notice that when certain functions such as MODES, DISP, MATRIX and other such selections are made, the top row of entry keys is used for selecting a menu item.
3)  EXIT:  The exit key is used to get out of the menu listing or other  non-standard entries.
4)  MODES:  The modes key is used to select the type of display such as Degrees, Radians, Rectangular, and polar.  Press the Red key; then the MODES key.  The top row of entry keys then becomes functional keys that correspond to the menu on the bottom line of the display.  
5)  The DISP key is used for selecting the number  type of display such as Scientific, Engineering,  and Fixed.
6)  Clear Key:  The clear key, the large left-pointing arrow is used to clear the X-entry.  You can use the Red function of that key to clear other entries.

A Few Words About RPN (Reverse Polish Notation): HP calculator gurus swear by  RPN, but most of us prefer the regular algebraic --some of us even to the hybrid type that has a few RPN and the rest algebraic.  Anyway, one of its features is that you don't use parentheses.  Basically, you tell the calculator what mathematical operation you're going to perform AFTER you enter the numbers.  Let's go right to doing some arithmetic.

Doing a Few Problems of Different Types:
1)  4 + 2:  Press the following keys:  4, ENTER, 2, +. You'll see the answer beside X.
2)  3 x 5:  3, ENTER, 5, x.  Notice that ENTER is NOT pressed after the last number.
3)  (7 + 5) ÷ (2 + 4):  7, ENTER, 5, +, 2, ENTER, 4, +, ÷ .  You'll notice that you enter divide in the last step.  4)  42 :  4, ENTER,  Red, x2 .   You can use this same procedure of entering a number and then the function with many of the keys, including these:  1/x, √x, LOG, LN, 10x , ex .
5)  25 : 2, ENTER, 5, yx
6)  √(-9) :  3,+/-, ENTER, √x .  Notice that the answer is given as a complex number in rectangular form.
7)  6! (6 factorial):  6, ENTER, Red, PROB, N!
8)  6P3 (Permutations of 6 things taken 3 at a time):  6, ENTER, 3, Red,  PROB , COMB.   Other statistics are done in a similar way.
9)  i98 :  1, Red, Complex, ENTER, 99, yx .  There may be better ways of doing this.
10)  Determinant of a  2 x 2 Matrix 1 ,2, 3 ,4:  Enter the dimension:   2, ENTER, 2, ENTER.  Red, MATRIX, NEW.  Enter data: 1, ENTER, XEQ (This is really the --> key), 2, ENTER, XEQ, 3, ENTER, XEQ, 4 ENTER, DET.  There may be other ways to do this, but this will work for any matrix.

This is the basics.  There are many other functions which should be become obvious if you understand the method in these. 
(15)  What does S-V.P.A.M. on the Casio scientific calculator s mean?
It's for sure you'll never find that information in the user manuals.  Actually, it stands for Super Visually Perfect Algebraic Method.  The Algebraic Method part applies to the idea that you can enter an expression the way you would write it down.  For example, if you wanted to find the sine of a 45 degree angle on some other scientific calculators, you would enter [9],[0], [sin],[=].  On the S-PAM you would enter [sin], [9],[0], [=], the way you would write it down.  The visually perfect allows you to have the entry and the answer both displayed at the same time.  Incidentally, this isn't just hype.  Both of those features are very useful features in my opinion.  The PAM for the Casio is about the same as EOS for the TI, if that means anything to you. (See Item 11 above.)
(16)  Will the Casio fx-7400G do fractions?
I think not.  Here's a short program you can enter if you have enough memory left.  It takes about 90 bytes of memory.  There are, no doubt, better programs, but this is a quick and dirty one that works.
Ans->A: 0->K:1->D:0->N
Lbl 1
Lbl 2
K>999=> Goto 3   (=>is not greater than or equal to, but the symbol gotten by SHIFT, 7.)
:T<0=>Goto 1
Lbl 3
  (▲ is the symbol gotten by SHIFT, :)
1.  The formatting leaves something to be desired, but it works after a fashion.  When -Disp- appears at
     the end of the program, press EXE to get the total answer.
2.  You must use the program immediately after you do the fraction operation so  that the correct answer
     will still be in the Ans location.
3.  With large numerators and denominators, the calculation takes quite some time, perhaps up to 30 or
     40 seconds.  But with small ones it's reasonably fast.
4.  You could change the number is the K> step to 99 if you want to limit the capability to smaller
5.  If there is no fractional equivalent, the program does not return the decimal, but gives you an
    incorrect answer. I did not want to use very scarce memory to do that, but you could add those
    steps if you want to use the memory.

Last Revised: 10/17/05