How to subtract fractions – Step By Step Guide

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Calculator basics are necessary to solve mathematical problems in a scientific calculator. Subtracting is the most common basic of mathematical calculation. Even a child can subtract between two numbers without any need of a calculator. So why do we need to learn this? The fact is becoming the most common mathematical basic subtraction has the most types of uses in mathematics.

That’s why we need to learn subtraction thoroughly. In this article I’m going to show how to subtract fractions with theory, formula, examples, steps by steps solution, getting result, alternative ways of doing these problems and so on.

How to subtract fractions – Step By Step Guide

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Well, subtraction is a process where you have to subtract a minuend from a subtrahend or something else. Sometimes subtraction gives us the idea of negative number. So in real world there is nothing called as negative number. There is a term called loss or lending amount. But in mathematics there is both positive and negative number it expands to positive infinity and negative infinity respectively.

Example: 20 – 9 = 11, 2 – 9 = -7(negative number)

So now it is time for another term called fraction. Fraction can be described as a ratio or a number which can be written in a/b form. Some examples of fraction are 1/2, 7/3, 5/9 etc. The upper part of the fraction is called as numerator. So in this case 1, 7 and 5 are numerator. The lower part of a fraction is called as the denominator. 2, 3, 9 are called denominator in this case. There are many types of fraction. They are proper fraction, improper fraction and mixed fraction.


what is subtracting fractions

Well we had a detailed introduction of subtraction and fraction. Now we are heading to subtraction of a fraction. Subtraction of a fraction means there would be at least one fraction number in the subtraction. The fraction can be the minuend and it can be subtrahend. Both of the minuend and subtrahend also can be fraction.

Formula: a/b – c/d = (ad – bc)/ bd

Example: : 5/2 – 3/5 = (25 – 6) / 10 = 19/10

This fraction related problems are very easy to solve in a scientific calculator. Most of the scientific calculators have a fraction button, “/” which can easily take the input as denominator and numerator. Some calculators don’t have that feature. In that case we have to use “÷” button for entering fraction. Let’s try to solve that example on a scientific calculator.

  Step-1 : Press the “On” button for turning on the scientific calculator

  Step-2 : Press the fraction button “/”

  Step-3 : Now enter the first fraction as minuend. For numerator, press “5” and then press the “Down Arrow”. After that, press “2” in the place of denominator

  Step-4 : Press the minus button “-“. After that, enter the subtrahend for subtraction

  Step-5 : To enter the subtrahend press fraction button “/” again

  Step-6 : Enter the second fraction as subtrahend. For numerator, press “3” and then press the “Down Arrow”. After that, press “5” in the place of denominator.

  Step-7 : Press the equals to, “=” to get the answer. The answer 19/10 will be shown at the screen.

  Alternative process (Without a fraction “/” button)

Step-1 : Press the “On” button for turning on the scientific calculator

Step-2 : Press the first bracket “(“. After that, enter the first fraction as minuend like this, “5” + “÷” + “2” respectively. Then close the bracket.

Step-3 : Press the minus sign “-“. After that, enter the subtrahend for subtraction

Step-4 : Press the first bracket “(“. After that, enter the second fraction as subtrahend like this, “3” + “÷” + “5” respectively. Then close the bracket.

Step-5 : Press the equals to button, “=” to get the answer

If your calculator doesn’t have the Math Print mode you won’t probably see the answer in a/b format. In that case the answer will be 1.9 at the screen.

Fraction is basically two kinds of. One of them is natural fraction and the other one is mixed fraction. Natural fraction is like ½(half) or ¼ (one fourth) etc. Mixed fractions are 3¼ (three of two fifth) 2⅔ (two of two third) etc. Fractions using a calculator are now easier than before.

Some calculators like Casio fx-100 ms calculator doesn’t have a proper fraction button. Its fractional expression is also not easily understandable. But calculators like Casio fx-991 ES, Casio fx-991 ES Plus, Casio fx-991 EX have a proper fraction button and it displays proper mathematical expression same as textbook.

Quick Comparison – Our Top 5 Calculator

How to use a calculator for fractions

Fractions calculator step by step (Addition Method)

Fractions calculator step by step (Subtraction Method)

This is also a very easy task to do in a calculator. At first let’s have a look at the formula.

Formula: a/b - c/d = (ad - bc)/bd

Example: 3/2 - 4/7 = (3x7 - 2x4)/7x2= (21-8)/14 = 13/14

To solve this problem in a calculator you have to follow this procedure:

  Step-1 : After turning on your calculator press the fractional button “/”

  Step-2 : Enter the value for first fraction in the both numerator and                                      denominator side. You have to press 3+ down arrow+ 2 to enter first                    fraction.

  Step-3 : Press “-” and then press fractional button “/” again.

  Step-4 : Enter the second fraction as like as you did before for first fraction.                         Enter the values 4 and 7.

  Step-5 : Press “=” button.

  Result: The answer will show at screen. It will be 13/14

Fractions calculator step by step (Multiplication Method)

Multiplication is also as easy as the other described operations before. But getting result may vary sometimes. But at first let’s have a look at the formula.

Formula: a/b x c/d = ac/bd

Example: 3/2 x 4/7= 12/14 = 6/7 (N.B: The calculator will always give the simplified result)

To solve this problem in a calculator you have to follow this procedure:

  Step-1 : After turning on your calculator press the fractional button “/”

  Step-2 : Enter the value for first fraction in the both numerator and                                      denominator side. You have to press (3+ down arrow+ 2) to enter first                  fraction.

  Step-3 : Press “x” and then press fractional button “/” again.

  Step-4 : Enter the second fraction as like as you did before for first fraction.                        Enter the values 4 and 7.

  Step-5 : Press “=” button.

  Result: The answer will show at screen. It will be 6/7

Fractions calculator step by step (Division Method)

Well, when it comes to the division we have to be careful about this. It is also very easy task. But lack of knowledge and a wrong input will give you a wrong result. The formula is given below.

Formula: a/b ÷ c/d = ad x bc

Example: 3/2 ÷ 4/7 = 3 x 7/ 4 x 2 = 21/8

To solve this problem in a calculator you have to follow this procedure:

  Step-1 : After turning on your calculator press the fractional button “/”

  Step-2 : Enter the value for first fraction in the both numerator and                                      denominator side. You have to press (3+ down arrow+ 2) to enter first                  fraction.

  Step-3 : Press “÷” and then press fractional button “/” again.

  Step-4 : Enter the second fraction as like as you did before for first fraction.                        Enter the values 4 and 7.

  Step-5 : Press “=” button.

  Result: The answer will show at screen. It will be 21/8

Some extra useful operations of fraction

Fraction of complex number

Remember! If you want to do complex number related fraction calculation, your calculator must remain in the complex mode. To set your calculator to complex mode follow this procedure.

  Step-1 : Turn on the calculator. Press the Menu or MODE button.

  Step-2 : Choose the CMPLX mode. Find where it is.

  Step-3 : Press Esc or EXIT. Now you are well set.

  I will talk about a complex division. It will be two complex numbers is divided by a fraction. Now imagine 3+2i as a numerator and 2+3i as a denominator where “i” is an imaginary number. The expression will be like “(3+2i)/ (2+3i)”. Let’s solve this in a calculator.

To solve this problem in a calculator you have to follow this procedure:

  Step-1 : After turning on your calculator press the fractional button “/”

  Step-2 : Enter the value for first complex number in the numerator. You have                     to press (“3”+ “+” + “2”+ “i”) to enter first fraction.

  Step-3 : Press “Down Arrow” and then input the second complex number                          again.

  Step-4 : : Enter the second complex number as like as you did before for first                      complex number. Enter (“2” + “+” + “3”+ “i”).

  Step-5 : Press “=” button.

  Result: The answer will show at screen. It will be (12/13) - (5/13)i

Mixed fraction

Sometimes a fractional number will be expressed as a mixed fraction. Let’s have a look what is it. If 5/2 is expressed as 2½ then we will call 2½ a mixed fraction. The formula is simple.

Formula: a b/c = {(a x c) + b}/c

Example: 2 ½ = {(2x2) + 1}/2= 5/2

To do these in your calculator try this method.

  Step-1 : Press “SHIFT”+ “/” after turning on your calculator.

  Step-2 : Input 2 as the first number. Then enter the numerator as 1 and                              denominator as 2 like before.

  Step-3 : Press “=” button.

Result: The result will be 5/2 and it will be shown at the screen

Equivalent fractions

Equivalent fraction means multiplying or dividing the numerator and denominator with the same number.

Formula: a/b = (a x d)/ (b x d) or a/b = (a ÷ d)/(b ÷ d)

Example: 2/3 = (2x5)/ (3x5) = 10/15 or, 10/15 = (10÷5)/ (15÷5) = 2/3

To solve this problem in a calculator you have to follow this procedure

  Step-1 : After turning on your calculator press the fractional button “/”.

  Step-2 : Enter the value for first fraction in the both upper and lower side. You                  have to press “10” + “÷” + “5” for numerator.

  Step-3 : Press “15” + “÷” + “5” for denominator.

  Step-4 : Press “=” button.

Result: The answer will be shown at screen. It will be 2/3.

See! How easy to do fraction in calculator. So there is no need to worry about it anymore. Also there are some other types of calculations for fraction. But these are the basics of fraction calculation.
I hope I have told everything about this method. I guess formulas and examples will also help you to understand this properly. Now fractions using a calculator will be much easier. It is enough for today. Thanks for reading.

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