Grade 5

Grade 5


Fractions


Fractions are a way of representing parts of a whole. When we talk about fractions, we are discussing how many parts of a certain size there are in something. Fractions can be used in many everyday situations, such as cooking, dividing a pizza, reading a clock, and much more.

What is fraction?

In the simplest sense, a fraction is a number that represents a part of a whole. It is used to show how many parts we have out of a certain number of equal parts. A fraction is made up of two main components: the numerator and the denominator.

Fraction example: Let's look at the fraction 3/4. Here, 3 is the numerator, and 4 is the denominator.

Meter

The numerator is the top number in a fraction. It tells us how many parts we have. In the fraction 3/4, the number 3 is the numerator. This means we have 3 parts.

Divisor

The denominator is the bottom number in a fraction. It tells us how many equal parts the whole number is divided into. In the fraction 3/4, the number 4 is the denominator. This means the whole number is divided into 4 equal parts.

Fraction table:

Whole | Parts taken | Fractions
1 | 1 | 1/1
1 | 2 | 1/2
1 | 3 | 1/3
1 | 4 | 1/4
1 | 5 | 1/5
    

Reading and writing fractions

When writing or reading fractions we usually say the numerator first and then the denominator. For example:

  • 1/2 is read as "half."
  • 3/4 is read "three quarters."
  • 5/8 is read as "five eighths."
  • 7/10 is read "seven tenths".

Visualization of fractions

Fractions are easier to understand when we can visualize them. Below is an example of a pie chart representation of the fraction 1/4.

In this circle, the shaded area represents 1/4 of the whole.

Similarly, we can represent other fractions also using visual charts.

Equivalent fractions

Sometimes, different fractions can represent the same quantity. Such fractions are called equivalent fractions. For example, 1/2 is equal to 2/4, 3/6 or 4/8. They all mean the same thing.

Example of equivalent fractions:

1/2 = 2/4 = 3/6 = 4/8
Each of these fractions is equivalent. They all represent the same part of a whole.
    

Comparing fractions

We often have to compare fractions to find out which fraction is bigger and which is smaller. There are several ways we can do this.

Method 1: Common denominator

The primary method of comparing two fractions is to change them to a common denominator. Once the denominators are the same, we can compare the numerators directly.

Example of comparing fractions:

Let's compare 2/3 and 3/4. We can find a common denominator of 12:

2/3 = 8/12 (Multiply both numerator and denominator by 4)
3/4 = 9/12 (Multiply both numerator and denominator by 3)

Now compare: 8/12 < 9/12. Therefore, 2/3 < 3/4.
    

Method 2: Cross-multiplying

Another method is cross-multiplication. Multiply the numerator of each fraction by the denominator of the other fraction.

Example of cross-multiplication:

Compare 1/3 and 2/5:

1 * 5 = 5
2 * 3 = 6

Since 5 < 6, we conclude that 1/3 < 2/5.
    

Adding and subtracting fractions

Adding or subtracting fractions requires a common denominator. With the same denominator, you add or subtract fractions.

Adding fractions with the same denominators

Example of adding fractions: 1/4 + 2/4

1/4 + 2/4 = (1+2)/4 = 3/4
    

Subtracting fractions with the same denominators

Example of subtracting fractions: 3/5 - 1/5

3/5 - 1/5 = (3-1)/5 = 2/5
    

Adding or subtracting fractions with different denominators

Example: Add 1/2 and 2/3.

Find a common denominator: lcm(2, 3) = 6

1/2 = 3/6 
2/3 = 4/6 

so,
1/2 + 2/3 = 3/6 + 4/6 = 7/6 or 1 1/6
    

Multiplication of fractions

Multiplying fractions is easier than adding or subtracting. You just multiply the numerators and multiply the denominators.

Example of multiplying fractions: 2/3 and 3/5

(2/3) * (3/5) = (2*3) / (3*5) = 6/15 = 2/5 (after simplification)
    

Division of fractions

To divide a fraction by another fraction, the first fraction has to be multiplied by the reciprocal of the second fraction.

Example of dividing fractions: divide 4/5 by 2/3

4/5 ÷ 2/3 = 4/5 * 3/2 = (4*3) / (5*2) = 12/10 = 6/5 or 1 1/5 (after simplification)
    

Converting improper fractions and mixed numbers

An improper fraction is a fraction in which the numerator is greater than or equal to the denominator. A mixed number contains a whole number and a fraction. They can be converted from one to the other.

Conversion example: Convert 7/4 to a mixed number.

7/4 = 1 3/4
1 full part + 3 parts of 4
    

Conversely, convert a mixed number to an improper fraction:

Example: Convert 1 1/2 to an improper fraction.

1 1/2 = (1*2 + 1)/2 = 3/2
    

Conclusion

Fractions are a fundamental part of mathematics and provide a means of expressing parts of a whole in different ways. By understanding the various concepts related to fractions - including equivalent fractions, addition and subtraction, multiplication and division, and converting between improper fractions and mixed numbers - you can build a strong foundation for tackling more complex mathematical ideas in the future.


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