Decimal To Fraction Formula: Conversion, Methods

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Jasmine Grover

Education Journalist | Study Abroad Lead

Decimal and Fractions are both rational numbers, however, they both are different from each other. Fraction is the division of two numbers. Fractions are represented in two parts; the upper part is called the numerator and the lower part is called the denominator. On the other hand, a decimal number is also separated into two parts separated by a decimal point; the digits which are on the left side are the whole number whereas the number on the right side represent the fractional part. The conversion of decimals to fractions is one of the most commonly carried out steps in Arithmetic. With the help of strong division basics, one can easily convert decimals to fractions, as well as fractions to decimals.

Key Terms: Decimals, Fractions, Mixed Fractions, Recurring Decimal, Negative Decimals, Conversion, Simplest Form, Numerator, Denominator, Terminating Decimals

Also read: Isosceles Triangle Theorems


What are Decimals?

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The number which comes in between integers and non-integers is called a decimal number. The dot represent in between numbers is called the decimal point. For Example, 34.5 is a decimal number. Here, 34 represent the whole number and 5 is the fractional part.

There are two types of decimal numbers basically, 

  • Recurring Decimal Numbers- The repeating and non-terminating decimals are called Recurring Decimal Numbers.
  • Non-Recurring Decimal Numbers- The non-repeating and terminating decimals are called Non-Recurring Decimal Numbers.

Decimals

Decimals

Read More: Difference Between Fraction and Rational Numbers


What are Fractions?

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The number is expressed as a quotient, in which there is a numerator and denominator. A fraction has two parts; the upper part is called Numerator and the lower part is called the Denominator. 

The types of fractions are elaborated below: 

  • Unit Fraction- Fraction which has 1 as a numerator is called a unit fraction. 
  • Proper Fraction- Fractions in which the numerator is less than the denominator is called proper fraction.
  • Improper Fraction- Fraction in which numerator is more than dominator is called Improper Fraction.
  • Mixed Fraction- Mixed fractions consist of a whole number along with a proper fraction.

Types of Fraction

Types of Fraction

Read More: How to Rationalize the Denominator?


How To Convert Decimals Into Fractions?

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To convert a decimal into a fraction we need to follow three simple steps:

  • Step 1: First, write the Decimal number without the Decimal point in the numerator. 
  • Step 2: Count the numbers after the decimal point to the right side and put that many zeroes in the Denominator.
  • Step 3: Then reduce the fraction in simplest form

For Example: Let us convert 30.5 into fractions. 

  • Step 1: Write the decimal number without a decimal point in the numerator which means 30.5 will be written as 305.
  • Step 2: Since there is one number after the decimal, the denominator will be 10. 
  • Step 3: The fraction obtained now needs to be reduced in the simplest form as follows 

30.5 = \(\frac{305}{10}\) = \(\frac{6}{12}\)

Conversion of Decimals to Fractions

Conversion of Decimals to Fractions

Read More: Addition and Subtraction of Integers

Conversion of Repeating Decimals to Fractions

Repeating Decimals, also known as Recurring Decimals, are those decimal numbers that do not end after a finite number of decimal places and keep on repeating in the number. 

In order to convert repeating decimals to fractions, here is an example to understand the procedure. 

Let us convert 0.77777... to a fraction.

Let x = recurring number, 0.77777..

Let n= the number of recurring digits, i.e. 7

Now, Multiply the recurring decimal number by 10, i.e.,

10 x = 10 x 0.77777 = 7.77777...

This means that 

10x - x =7

9x = 7

∴ x= 7/9

Read More: Decimal Expansion of Rational Numbers

Conversion of Decimals to Mixed Number Fractions

Decimals that have values greater than 1 can be converted and written as mixed fractions. Here are the steps to convert decimal numbers into mixed fractions:

  • Step 1: Firstly, we have to consider the whole number part and decimal part of the decimal number separately.
  • Step 2: Write the decimal number without a decimal point in the numerator and count the numbers after the decimal point to the right side and put that many zeroes in the Denominator.
  • Step 3: Now, the next step is to simplify the fraction obtained.
  • Step 4: Lat step involves attaching the whole number part of the original number with the fraction obtained after simplification. 

Mixed Fractions

Mixed Fractions

Let's Convert 2.5 into a mixed fraction.

Consider 2 and 0.5 separately.

Now, 0.5 can be written as 5/10 in fractional form. 

Simplify the fraction as 

5/10 = 1/2

Last step is to attach the whole number to the simplified fraction as given below: 

2+1/2= 2\(\frac{1}{2}\)

Read More: Multiplicative Inverse

Conversion of Negative Decimal to a Fraction

Given below are the steps to convert any negative decimal number to a fraction:

  • Step 1: First, remove the negative sign from the decimal number.
  • Step 2: Now, you have to do the conversion of decimals to fractions as explained in the above steps. 
  • Step 3: Put the negative sign to the fraction obtained.

Let us convert -3.2 into a fraction.

First, we will remove the negative sign and will consider it as 3.2

As there is only one digit after the decimal, the fraction would be 32/10.

Convert 32/10 to its simplest form, i.e, 

32/10 = 16/5 

Now, apply a negative sign to the fraction.

16/5 = -16/5

Read More: Irrational Numbers


Things to Remember

  • Decimal and fractions are both different from each other. Decimal and fraction are both Rational numbers.
  • The number which comes in between integers and non-integers is called a decimal number. There are two types of decimal numbers- Recurring and non-recurring. 
  • A fraction has two parts; the upper part is called Numerator and the lower part is called the Denominator. The types of fractions are- unit, proper, improper and mixed fraction. 
  • In order to convert decimals to fractions, we have to write the Decimal number without the Decimal point in the numerator. 
  • The next step is to count the numbers after the decimal point to the right side and put that many zeroes in the Denominator.
  • Lastly, we have to reduce the fraction in the simplest form.
  • The same process of conversion is followed for negative decimals too. 

Read More: Minors and Cofactors


Solved Examples

Ques. Convert 0.5 into Fraction. (3 Marks)

Ans. To convert decimal into fraction, 

First, we will write the decimal number without a point, i.e, 0.5 will be written as 5. 

Since there is one number after the decimal, the denominator will be 10. 

0.5 = \(\frac{5}{10}\)

Now, we will simplify the fraction as 

0.5 = \(\frac{5}{10}\) = \(\frac{1}{2}\)

Ques. Convert 0.75 into Fraction. (2 Marks)

Ans. Write the number without a decimal point and then count the number of zeroes after the point and put that many zeroes in the denominator and simplify the fraction. 

0.75= \(\frac{75}{100}\) = \(\frac{3}{4}\)

Ques. Convert -3.2 into fractions. (3 Marks)

Ans. Since this is a negative decimal, so first we will write the number without the negative sign. 

 -3.2 = 3.2

Now, write the number without a decimal point and put the number of digits after decimal in the denominator as zeroes. -3.2 = 3.2 = \(\frac{32}{10}\)

Write the fraction in its simplest form as the last step. 

 -3.2 = 3.2 = \(\frac{32}{10}\) = \(\frac{16}{5}\) =-\(\frac{16}{5}\)

Ques. Convert 4.75 into a fraction. (3 Marks)

Ans. To convert 4.75 into fractions, 

Step 1: 4.75 will be as 475. 

Step 2: Since there are two numbers after the decimal, the denominator will be 100. 

4.75 = \(\frac{475}{100}\)

Step 3: Simplify the fraction as 

4.75 = \(\frac{475}{100}\) = \(\frac{19}{4}\)

Ques. Convert 0.625 into a fraction. (3 Marks)

Ans. To convert 0.625 into a fraction,

Step 1: 0.625 will be as 625. 

Step 2: Since there are three numbers after the decimal, the denominator will be 1000. 

0.625 = \(\frac{625}{1000}\)

Step 3: Simplify the fraction as 

0.625 = \(\frac{625}{1000}\) = \(\frac{25}{40}\) =\(\frac{5}{8}\).

Ques. Convert 0.333 into a fraction. (3 Marks)

Ans. To convert 0.333 into a fraction,

Step 1: 0.333 will be as 333. 

Step 2: Since there are three numbers after the decimal, the denominator will be 1000. 

0.333 = \(\frac{333}{1000} \)

Step 3: Since the fraction cannot be simplified, the fraction will be as 

0.333 = \(\frac{333}{1000} \)

Ques. Convert 0.35 into a fraction. (3 Marks)

Ans. To convert 0.35 into a fraction,

Step 1: 0.35 will be as 35. 

Step 2: Since there are two numbers after the decimal, the denominator will be 100. 

0.35= \(\frac{35}{100}\)

Step 3: Simplify the fraction as 

0.35= \(\frac{35}{100}\) =\(\frac{7}{20}\).

Ques. Convert 4.75 infractions and also convert them into mixed fractions. (3 Marks)

Ans. To convert 4.75 into a mixed fraction,

Step 1: 4.75 will be as 475. 

Step 2: Since there are two numbers after the decimal, the denominator will be 100. 

4.75= \(\frac{475}{100}\)

Step 3: Simplify the fraction as 

4.75= \(\frac{475}{100}\) =\(\frac{19}{4}\)

Step 4: In mixed fractions, it would be written as 434 

Ques. Convert 0.225 into a fraction. (3 Marks)

Ans. To convert 0.225 into a fraction,

Step 1: 0.225will be as 225. 

Step 2: Since there are three numbers after the decimal, the denominator will be 1000. 

0.225= \(\frac{225}{1000}\)

Step 3: Simplify the fraction as 

0.225= \(\frac{225}{1000}\) =\(\frac{9}{40}\).

Ques. Convert 0.0035 in the simplest fraction. (3 Marks)

Ans. To convert 0.0035 in the simplest fraction,

Step 1: 0.0035 will be as 35. 

Step 2: Since there are four numbers after the decimal, the denominator will be 10000. 

0.0035= \(\frac{35}{10000}\)

Step 3: Simplify the fraction as 

0.0035= \(\frac{35}{10000}\) =\(\frac{7}{2000}\).

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