Grade 3

Grade 3Fractions and Decimals


Understanding Fractions


Fractions are a way of representing parts of a whole. When we divide something into equal parts, each part is a fraction of the whole. Fractions are used in everyday life, from cutting pizza into slices to measuring ingredients for a recipe.

What is fraction?

A fraction is made up of two numbers, one above the other, separated by a line. The number on top is called the numerator, and the number on the bottom is called the denominator.

  meter
  ,
  Divisor

The numerator tells us how many parts we have. The denominator tells us how many equal parts the whole is divided into.

Example 1:

Suppose we have a pizza that is divided into 4 equal slices. We are left with 1 slice. How can we express this as a fraction?

Numerator = 1 (number of slices we have)

Denominator = 4 (total number of slices)

Fraction: 1/4

Types of fractions

There are different types. Here are some:

Proper fractions

In proper fractions the numerator is smaller than the denominator. They are less than 1.

Example: 
  1/4, 2/5, 3/8

Improper fractions

Improper fractions have a numerator greater than or equal to the denominator. They are equal to or greater than 1.

Example: 
  5/4, 6/5, 8/8

Mixed number

Mixed numbers are a combination of a whole number and a proper fraction.

Example: 
  1 1/2, 3 3/4, 5 2/3

Example 2:

Convert the improper fraction 9/4 to a mixed number.

Divide 9 by 4. The quotient is 2 and the remainder is 1.

So, 9/4 = 2 1/4

Equivalent fractions

Equivalent fractions have different numerators and denominators but they represent the same value.

Example 3:

Let's consider the fraction 1/2.

If we multiply the numerator and denominator by 2 we get 2/4.

If we multiply the numerator and denominator by 3 we get 3/6.

Therefore, 1/2, 2/4 and 3/6 are like fractions.

Adding fractions

When adding fractions, the denominators must be the same. If this is not the case, find the same denominators by finding the least common multiple.

Example 4:

Let's add 1/4 and 1/2.

The least common multiple of 4 and 2 is 4.

Convert 1/2 to 2/4.

Now add: 1/4 + 2/4 = 3/4

Subtracting fractions

As with addition, make sure the denominators are the same before subtracting fractions.

Example 5:

Let's subtract 1/3 from 3/4.

The least common multiple of 4 and 3 is 12.

Convert 3/4 to 9/12.

Convert 1/3 to 4/12.

Now subtract: 9/12 - 4/12 = 5/12

Multiplication of fractions

To multiply fractions, multiply the numerators together and the denominators together.

Example 6:

Let's multiply 1/2 by 2/3.

Multiply the fractions: 1 * 2 = 2

Multiply the denominators: 2 * 3 = 6

Product: 2/6, which simplifies to 1/3

Division of fractions

To divide fractions, multiply by the reciprocal of the fraction you're dividing by.

Example 7:

Let's divide 3/4 by 1/2.

The reciprocal of 1/2 is 2/1.

Multiply: 3/4 * 2/1 = 6/4, which simplifies to 1 1/2

Understanding fractions on the number line

Fractions can also be represented on the number line, which helps in understanding the size of fractions.

Example 8:

Let's locate 1/4, 1/2 and 3/4 on the number line.

    0 |---|---|---|---|---| 1
      0 1/4 1/2 3/4 1
    

Uses of fractions in real life

Fractions are used in many real-life situations:

  • Cooking: Recipes often call for fractions to measure ingredients, such as 1/2 cup sugar.
  • Time: A quarter of an hour represents 1/4 of an hour.
  • Purchases: Sometimes discounts are given in fractions, such as 1/3 off.
  • Construction: The measurement may involve different parts, such as cutting a piece of wood 3/8 meter long.

By understanding fractions we can solve many real-life problems more easily and with confidence.

Review of fractions

Fractions are a fundamental concept in math that helps us understand parts of a whole. Whether it's understanding pizza slices or scaled models, fractions are everywhere, and the more comfortable we are with them, the better!

Practice working with fractions regularly through exercises, and try to recognize the fractions around you. With time and practice, understanding fractions can become as natural as counting whole numbers.


Grade 3 → 2.1


U
username
0%
completed in Grade 3


Comments