Calculator rounds up fractions when adding or subtracting numbers

Minus and change-sign are two completely different things. Minus is used to subtract one number from another. When you press minus when the input line is empty, your telling the calculator to subtract. The only way it can subtract the number you're about to put in is to subtract it from something else, and that something else is the previous answer, hence the "Ans."

If you want to input a negative number, use the change-sign key. If you want to subtract one number from another number, use the minus key.

Try pressing the plus key when the input line is empty. You'll get Ans+ in this case as well, The same with multiply and divide, among others, and for the same reason.

How to Use a TI-30XA
The TI-30XA is a scientific calculator with many functions. You can calculate problems with fractions and decimals, as well as solve problems of probability and functions. A scientific calculator computes the number sentence you type in using the order of operations: parentheses first, then roots and exponents, then division and multiplication and, finally, addition and subtraction.

Instructions

1. How to Use a TI-30XA
   • 1

     Press the [ON/C] key to turn on the calculator. Press the [OFF] key to turn it off. To use the calculator in solar mode, put the solar panel in the light and then press the [ON/C] key. To turn it off when in solar mode, slide the calculator cover back on and it will automatically shut off.
     

   • 2

     Replace the batteries by first removing the cover and placing it face down. Use a Phillips-head screwdriver to unscrew the back panel. Remove the back panel and change the batteries. Screw the back panel back on. Press [OFF] [ON/C] and [ON/C].
     

Use the basic operation keys for addition [+], subtraction [-], multiplication [x] and division [/]. To change the signs of your values from positive to negative or vice versa, press the [+ -] key before the numbers you enter. Use the parentheses, [(] and [)], to command the calculator to solve what is inside the parentheses first. Press the [=] to solve the number sentence you entered into the calculator.

4

Find percents of a number by first typing in the number, then [x], then the percent number, [2nd], [%] and, finally, [=]. The [2nd] key allows you to use the commands that are written above each key. For example, to find 20% of 100, type in 100 [x] 20 [2nd] [%] [=] and the display will show the answer, 20.

5

Turn decimals into fractions by entering the decimal value, then pressing the [2nd] and [F D] keys, then [=]. Turn the fraction back into a decimal by pressing [2nd] and [F D] again. For example, to turn 0.5 into a fraction, type in 0.5 [2nd] [F D] [=].

6

Turn mixed numbers into improper fractions by entering the mixed number first. Type in the whole number, then the [a b/c] key, then the numerator, the [a b/c] key again and the denominator. Next, press [2nd] [d/c] [=], and the calculator will convert your mixed number into an improper fraction. Press [2nd] [d/c] again to turn it back into a mixed number. For example, to turn 1 1/2 into an improper fraction type in 1 [a b/c] 1 [a b/c] 2 [2nd] [d/c] [=], and the display will show the answer 3/2.

7

Switch the notation setting of the calculator between engineering, scientific and floating. To select scientific notation, press the [2nd] and [SCI] keys; this will display your answers in scientific notation as a number between 1 and 10 to a power of 10. Press [2nd] [ENG] to switch to the engineering setting; this setting displays values as a number with an exponent that is a multiple of 3. Press [2nd] [FLO] to switch to the floating setting. This is considered standard notation and will display the answer as a standard number.

8

Use the left arrow key to go back and delete numbers to the right of the cursor that you typed into the display. This must be done before you press [=]. To clear the screen, values and operations, press [ON/C] and [ON/C] again in battery mode, or [CE/C] and [CE/C] again in solar mode.

Hope it helps your problem. Thanks!

Finding the remainder from a division calculation is often referred to as using the MOD function, though this isn't available directly on the fx-991ES.
To obtain the remainder, for example when dividing 10 by 7, you can only divide 7 into 10 once, leaving a remainder of 3.
For larger numbers, eg when dividing 389487 by 31 (equivalent to 389487MOD31) the division gives an answer of 12564.09677 (on the display), however you only want the fractional part so subtract 12564 to give 0.0967741935 . This includes the lower value digits that were previously hidden. Then multiply this result by 31 which gives 2.999999999 on the display. Since the result of a MOD or remainder calculation involving integers has to be a whole number, the answer needs to be rounded to 3. If the answer doesn't easily round to a whole number, it is likely that you have gone beyond the calculator's working capacity.
An alternative method which avoids the rounding of the fractional part is to take the integer part of the first result (12564) and multiply it by 31 to get 389484, then subtract this from 389487, giving the answer of 3.

TI-5045 SV
ii
English.............................................................. 1
Fran?ais ............................................................ 6
Espa?ol ............................................................. 11
Portugu?s ........................................................... 16
Examples, exemples, ejemplos, exemplos .............................. 21
ILLUSTRATIONS ¦ FIGURES ¦ ILUSTRACIONES¦ ILUSTRA??ES
Removable tab
Languette
Leng?eta extracci?n
Alavanca usada para o rolo
Ink roller
Rouleau encreur
Tamp?n de tinta
Cartucho de tinta
1
English
Your Texas Instruments calculator has a built-in printer for producing a permanent record printout of
your calculations with negative numbers printed in red. A big, easy-to-read display also enables you to
check entries or perform quick calculations without printing.
GETTING STARTED
OFF ON PRT IC GT
POWER
1. Connect the calculator to a proper power outlet (110-120V or 220-240V
where available).
2. The calculator is turned on by setting the POWER switch to the PRT
position.
Inserting the paper (see illustrations 1, 2, 3, and 4 on page ii).
1. Turn on the calculator.
2. Open the printer compartment cover by pressing down on its front edge and sliding it back in the
direction of the arrow.
3. Fit the roll of paper on the holder so that it unrolls from the bottom, with the loose end toward the
calculator.
4. Cut the end of the paper squarely and insert it firmly into the printer slot on the back of the
calculator.
5. Press & until the paper is in the printing position.
Replacing the ink roller (see illustrations 5 and 6 on page ii)
1. Turn the calculator off and tear off the excess paper.
2. Remove the printer cover by pressing down on both sides of the front edge and sliding back in the
direction of the arrow.
3. Remove the old ink roller by lifting it with the removal tab.
4. Insert the new ink roller into the compartment and press down gently until it snaps into place. Close
the printer compartment.
Note: The old ink rollers should not be refilled. Replacement rollers can be obtained from your local
retailer. The warranty does not cover ink roller replacement.
2
SELECTION SWITCH SETTINGS
OFF ON PRT IC GT
POWER ROUND
: 5/4 9 + F 0 2 3
DECIMAL
4
TAX
SET CALC
Set the POWER, ROUND, DECIMAL and TAX switches as required.
Note: The TAX switch is spring-loaded to return to CALC when it is moved to SET and released.
The switch settings are summarized in the following table:
SWITCH SETTING FUNCTION
POWER ON
PRT
IC
GT
No printout is provided; however, the display can be printed by pressing
4.
The printer provides a printout of your calculations but does not count them.
The printer is on and an item count of additions and subtractions to or from
the register is printed when sub-totaled or totaled.
The GT position controls whether or not the totals from the independent add
register are accumulated in the grand total register.
ROUND Rounds the result of a calculation to the selected number of decimal places.
:
5/4
9
Truncates the result to the selected number of decimal places.
Rounds the result up or down according to its value. For example, when the
DECIMAL switch is set to 2, the result is rounded up if the third decimal
position is 5 or more and rounded down if it is 4 or less.
Rounds the result up to the selected number of decimal places.
Ex. 220 P 6
Setup: PRINTER: PRT, ROUND: :
DECIMAL: 2, TAX: CALC
Ex. 220 P 6
Setup: PRINTER: PRT, ROUND: 5/4
DECIMAL: 2, TAX: CALC
Press Display Printout Press Display Printout
2 0. 0¦ C
220 ' 220. 220¦ P
6 3 36.66 6¦ =
36¦66 ?
2 0. 0¦ C
220 ' 220. 220¦ P
6 3 36.67 6¦ =
36¦67 ?
DECIMAL + Add mode: All results are given with two decimal places. For addition and
subtraction only, a decimal point is automatically placed to the left of the last
two digits entered, unless the number already includes a decimal point.
F Floating mode: Any results are displayed and printed with the maximum
number of decimal places.
0 2 3 4 Fixed decimal mode: Sets the number of decimals to 0, 2, 3, or 4.
3
TAX SET
CALC
Lets you enter a tax rate to perform tax calculations.
Stores the tax rate. Pressing ! or " after a tax rate has been entered,
adds/subtracts the stored tax rate to/from the value in the display.
Ex. VAT = 17.5 %
100 + VAT
Ex. VAT = 17.5 %
235 - VAT
Setup: PRINTER: PRT, DECIMAL: F, ROUND: 5/4, TAX: CALC
Move and hold the TAX switch to SET. Press 217 L 5 and release the TAX switch. It
automatically returns to CALC. 17.5% is printed.
Press Display Printout Press Display Printout
2 0. 0¦ C
100! 117.5 100¦
17¦5 @
117¦5 ?
2 0. 0¦ C
235" 200. 235¦
N35¦ @
200¦ ?
Note: The most common setup is POWER: PRT, ROUND: 5/4, DECIMAL: 2, TAX: CALC. Use these
positions for the examples unless other settings are given.
KEY DESCRIPTIONS
Basic keys
I Clear Entry: Clears an entry, enabling you to enter another number in its place. Note
that this key does not clear the add register.
2 Clear Key: Clears the add register, any pending operations, and the display. 0.C is
printed. Does not clear the memory.
( Right Shift: Deletes the right-most digit entered from an entry before an operation key is
pressed. Shifts the remaining digits one place to the right.
L Decimal Point: Enters a decimal point.
4 Date/Non-Add: Prints a date (such as 12¦10¦96) or a number for reference purposes.
Does not affect calculations. This entry is printed on the left side of the printout, the date
or number preceded by the # sign.
& Paper Advance: Advances the printing paper.
Addition and subtraction keys
9 Add: Adds a number to the add register. Displays the cumulated result.
: Subtotal: Gives the intermediate total from the add register. Using this key does not
affect the contents of the add register.
. Subtract: Subtracts a number from the add register. Displays the cumulated result.
E Total: Gives the total from the add register, and then clears the register.
4
Multiplication, division, percent and margin keys
? Multiply: Multiplies the number in the display by the next value entered.
' Divide: Divides the number in the display by the next value entered.
3 Equals: Completes any pending multiplication or division operation.
> Percent: Calculates percentages, ratios, add-ons (e.g. of VAT), or discounts.
# Gross Profit Margin: Calculates the selling price of an item when its cost and gross
profit (or loss) margin are known; also used to obtain a price excluding VAT.
Ex.
Cost: 594
Profit margin: 40%
Press:2 594 # 40 3
Answer:
Selling price: 990
Gross profit: 396
Ex.
Selling price including VAT: 252
VAT %: 20%
Press: 252 # 20 . 3
Answer:
Selling price excluding VAT: 210
VAT: 42
/ Grand Total: Gives the grand total of the operations previously performed and stored in the
Grand Total register. Every time a total is obtained with E it is cumulated into this register
(printout shows G+) which is only cleared when / is pressed twice. During long
calculations, if / is not used, this re

Hi eamon at hom,

Doing fraction on the Sharp El 531W really isn't that bad. I had to use pictures because, the symbols will not transfer over to your posting for me to show you. When you select the [ON/C] this clears the calculator of previous calculations and, data so that they won't interfere with your new calculations.

Let take the first example where a mix number is being added to a improper fraction. Because I used the [a^b/c] key this makes the calculator display the answer in a mixed fraction format or, a proper fraction format. If I press the [a^b/c] key again after the answer the format will change to a decimal format. The fractional formats are displayed in a mixed number, improper or, proper fraction formats. A improper fraction is really a proper fraction number with the top number (numerator) is greater than or equal to the bottom number (denominator).

[ON/C] [3] [a^b/c] [1] [ [a^b/c] [2] [+] [4] [a^b/c] [3] [=] mixed number results. Now let's do the same calculation as a improper or, proper fraction format.
[ON/C] [7] [a^b/c] [2] [+] [2] [a^b/c] [3] [=] still a mixed number result. Even though I enter the fractions in a improper and, proper fraction formats the calculator will still display in a mixed number format. This is because the calculator first displays as a mixed number if it can. If it can't then it will display the value as a proper fraction and, never as a improper fraction. To convert from a mixed number to a improper fraction format if the calculator did not convert it to a proper fraction, I have to use [2ndF] [d/c] keys on the command line.



This show a little more complex raised power use of the [a^b/c] key.

This shows the [2ndf] [x^-1] keys being used to calculate fractions.


When I first saw this question being asked it, was answered with just use the / command. Which that isn't really a good answer because, in math we like to use elimination. If you use the / command eventually the numbers are going to be rounded off and, your not going to be able to eliminate anything. If you have any further question on how to preform fractions with this calculator be sure to post your comment and, I'll be glad to help.

The calculator has two Input/Output modes, MthIO and LineIO. In MthIO the results are displayed as fractions or as radicals or a mixture of fractions and radicals. What it means, is that in MthIO the calculator does exact calculations. Radicals in denominators are gotten rid of by rationalization, fractions are reduced to the same denominators before addition or subtraction. Fractions are reduced to simplest form.

In LineIO all results are displayed as decimal numbers.

If a result is exact (fractions and radicals) it can be changed to decimal form by pressing the S To D key, the one above the DEL key.

MthIO is the default IO mode. To set it, press SHIFT MODE and select 1:MthIO. To set LineIO as the IO mode, press SHIFT MODE and select 2:LineIO

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.

76.65*50*50*41

You can use the units menu (2nd > 3) to place a unit after some number you want to qualify as being an unit, or you can just type them in like 5_ft + 6_in. Note that you need to add on each part if you are doing mixed measurements; there is no _ft_in combination. So just add each manually - in your case you would do (5_ft + 6_in) - (2_ft + 8_in)

type the whole number then hit the ABC button then type the numerator then hit ABC then type the denominator


1ABC1ABC2 + 1ABC1ABC2=3