Question about Texas Instruments TI-86 Calculator

# Multiplication error(?) with repeating decimal place fractions.

When I enter 7*(-1/7)+1
I get a return of 2E-14

BUT
When I enter 7*-1/7+1
I get the expected return of 0

It is a problem with fractions that have repeating decimals and does not exist with fractions that terminate.

i.e.
6*(-1/6)+1
answer comes in as expected, at zero

What gives?

Posted by on

• Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

• Texas Instru... Master

Hello,
You may have guessed right. The presence of the parentheses makes the content of the parentheses evaluated first. So there is a loss of precision.
On the Ti92 I do 7*(-1/7)+1 and find 0.
But with Floating mode set at 12 decimal digits I get
1/7.=.142857142857.
Then .142857142857.*(-7) + 1 gives 2E-14.
Try to calculate pi*(-1/pi) +1 or e*(1/e)+1.

Posted on Sep 23, 2009

Hi,
a 6ya Technician can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
Goodluck!

Posted on Jan 02, 2017

×

my-video-file.mp4

×

## Related Questions:

### What is factoring and give the examples

Quick-Start Guide When you enter an expression into the calculator, the calculator will simplify the expression by expanding multiplication and combining like terms. At this point the calculator will attempt to factor the expression by dividing a G C F, and identifying a difference between two squares, or factorable trinomials. Use the following rules to enter expressions into the calculator. Variables Any lowercase letter may be used as a variable. Exponents Exponents are supported on variables using the ^ (caret) symbol. For example, to express x 2, enter x ^ 2. Note: exponents must be positive integers, no negatives, decimals, or variables. Exponents may not currently be placed on numbers, brackets, or parentheses. Parentheses and Brackets Parentheses ( ) and brackets [ ] may be used to group terms as in a standard expression. Multiplication, Addition, and Subtraction For addition and subtraction, use the standard + and - symbols respectively. For multiplication, use the * symbol. A * symbol is optional when multiplying a number by a variable. For instance: 2 * x can also be entered as 2x. Similarly, 2 * ( x + 5 ) can also be entered as 2 ( x + 5 ) ; 2 x * ( 5 ) can be entered as 2 x ( 5 ). The * is also optional when multiplying parentheses, example: ( x + 1 ) ( x - 1 ). Order of Operations The calculator follows the standard order of operations taught by most algebra books - Parentheses, Exponents, Multiplication and Division, Addition and Subtraction. The only exception is that division is not currently supported; attempts to use the / symbol will result in an error. Division, Square Root, Radi cals, Fractions Division, square root, radi cals, and fractions are not supported at this time. A future release will add this functionality.

that's all I can say basically I learned it this way.

Jul 09, 2015 | Office Equipment & Supplies

Tip

### Sharp ELW516: Changing the default display to decimal

<span><b>Getting Decimal Answers by Disabling WriteView<img src="elw516.gif" /> on the Sharp EL-W516 Calculator<br /><br /></b>The Sharp EL-W516's WriteView display uses multiple lines to display mathematics as it is seen on a page. Fractions are shown as fractions, exponents as exponents, integrals as integrals, and so on. This makes entering calculations easier, and reduces the chance of errors. <br /><br />At the same time, calculation results are displayed as fractions (or with roots or pi) whenever possible. Pressing the CHANGE button repeatedly will change these to decimal answers. <br />If you prefer to always get decimal results you need to <b>disable</b> <b>the WriteView display mode</b>. Doing this will make the calculator display like the Sharp EL-546W when in NORMAL mode. Answers will be given as decimals, but fractions will no longer look like fractions. In general, you will still need to follow the EL-W516 instructions.<br /><b>Disabling WriteView<br /></b><br />Press 2ndF and MATH to enter SET UP. Now press 2 for EDITOR.<br /><br />There are now two options: 0: W-VIEW, and 1: LINE<br /><br />Press 1 for Linear display mode to disable the WriteView display, and to get decimals as your answers.<br /><br />To return to the WriteView display, go through the steps above but press 0 for W-VIEW.<br /><br /><b>NOTE</b>: It is not possible to have decimals as the default answer form when in WriteView mode. <br /></span>

on Mar 04, 2011 | Sharp ELW516 Scientific Calculator

### How to fraction. where is the fraction key

This calculator is incapable of displaying simplified fractions (i.e. 1 ½), you will have to use the decimal value or contain your complex fraction in parenthesis. (i.e. (5/2).)

Mar 01, 2011 | Texas Instruments BA-II Plus Calculator

### My calculator will show fractions instead of decimals when doing division. How do I change that? There is a N1 displayed in the lower left corner also...I think that may be the problem

Getting Decimal Answers by Disabling WriteView on the Sharp EL-W516 Calculator

The Sharp EL-W516's WriteView display uses multiple lines to display mathematics as it is seen on a page. Fractions are shown as fractions, exponents as exponents, integrals as integrals, and so on. This makes entering calculations easier, and reduces the chance of errors.

At the same time, calculation results are displayed as fractions (or with roots or pi) whenever possible. Pressing the CHANGE button repeatedly will change these to decimal answers.
If you prefer to always get decimal results you need to disable the WriteView display mode. Doing this will make the calculator display like the Sharp EL-546W when in NORMAL mode. Answers will be given as decimals, but fractions will no longer look like fractions. In general, you will still need to follow the EL-W516 instructions.
Disabling WriteView

Press 2ndF and MATH to enter SET UP. Now press 2 for EDITOR.

There are now two options: 0: W-VIEW, and 1: LINE

Press 1 for Linear display mode to disable the WriteView display, and to get decimals as your answers.

To return to the WriteView display, go through the steps above but press 0 for W-VIEW.

NOTE: It is not possible to have decimals as the default answer form when in WriteView mode.

Feb 07, 2011 | Sharp ELW516 Scientific Calculator

### Convert .714285 to the fraction 5/7?

Say you have a repeating decimal number 0.714285 714285 714285 etc. You identify the period (the repeating part) and in this case it is 714285.
Y
ou count the number of decimal places in the period: here it is 6. Your equivalent fraction is
Fraction= period/(99...9) where the number of 9's in the denominator is equal to the number of decimal places in the period. For this case, that is 6.
Thus
0.714285 714285 714285 etc.= 714285 / 999999

Reduce the fraction and you will find 5/7

This technique works for a repeating decimal number where the period starts just after the decimal mark.

If the periodic part does not start right after the decimal mark there are modifications to be made.

Jan 16, 2011 | Office Equipment & Supplies

### Can this convert decimal measurements to fractions of an inch

Enters a proper or improper fraction,
b?c (b { 6 digits, c { 3 digits). When
possible, improper fractions are
displayed as mixed numbers.
3 F 4 3?4
8 3 J 21?4
Single-variable functions display
decimal results.
1 F 2 0 0.25
a F b F c Enters the mixed fraction a b?c.
(a, b, c { 3 digits each, with the total
digits { 8).
6 F 4 F 6 64?6
J 62?3
"s Toggles display between a mixed
number and an improper fraction.
30 F 4 30?4
"s 71?2
"s 15?2
"s 71?2
"y Toggles display between fraction and
decimal.
55 F 24 55?24
"y 2.291666667
"y 27?24
If a result would overflow or if fixed decimal is 0, no
fraction to decimal conversion occurs. It is not an error.
Denominator must be a whole number {999.

Nov 28, 2010 | Texas Instruments TI-30XA Calculator

### How do you put in a fraction to mulitiply it by another fraction?

A fraction is just a particular number.
1. Enter numerator of first fraction
2. Press the division sign
3. Enter the denominator of first fraction
4. Press the multiplication key
5. Enter second numerator
6. Press the division key
7. Enter the denominator of second fraction
8. If you want a decimal result press [ENTER]
9. However, if you want a fraction press [MATH][1:

Sep 21, 2010 | Texas Instruments TI-83 Plus Calculator

### How do i do fractions with this calculator? there are so many keys i dont know what to push.

The primary key to enter something that resembles a fraction is the division key, the one above the multiplication key.
However, any division you enter yields a decimal number, unless the result is an integer.

To keep the result of a division as a (reduced) fraction use the [|=>Frac] or [ToFrac] command. It is accessible by the following key sequence
[MATH][1:ToFrac].
Insert it after the fraction, before pressing the [ENTER] key to get the result.

By pressing [MATH][2:ToDec] you convert a fraction in to a decimal number.

Apr 10, 2010 | Texas Instruments TI-83 Plus Calculator

### I can't find this button on my calculator / this

A fraction is in fact a ratio of two number: a division of a numerator by a denominator. The key used for the division operation is the one above the multiplication sign and below the caret [^], and in thee rightmost column of keys.

Beware that this calculator converts any ratio of two numbers into a decimal value. To keep a fraction in a fraction form you must use the [|=>Frac] or [ToFrac] command. To convert a decimal result to a fraction, use the [|=>Dec] command.
These commands are accessible through the CATALOG or more easily by pressing [MATH] (under the ALPHA key) and selecting [1:|=>Frac], or [2:|=>Dec]
Ex: to keep 27/48 in fraction form you enter
27 [/] 48 [MATH][1:|=>Frac] [ENTER]. Result is 9/16
You will notice that the resulting fraction is reduced to its simplest form.
To convert the above result from fraction to decimal press [MATH][2:|=>Dec]

A fraction can always be approximated by a decimal value but the converse is not always possible.

Jan 23, 2010 | Texas Instruments TI-84 Plus Calculator

### How do you subtract fraction on a caluclator. problem: 6/7-2/5

A fraction is just a number like (almost) any other. On most calculators, as you enter 6/5 the calculator displays its decimal value. When you press - the calculator waits for a number 2 then / then 5. Once you press the equal sign it will calculate 2/5 then subtracts it from the preceding result. The priority rules favor multiplication and division over addition and subtraction.

On some calculators you can keep a fraction in fraction format and operate on it with other fractions, and the result may be obtained as a fraction.
The gist of the story is that ON A CALCULATOR operations on fractions as performed like operations on any number.

Dec 20, 2009 | Sharp Office Equipment & Supplies

## Open Questions:

#### Related Topics:

164 people viewed this question

Level 3 Expert

Level 2 Expert