What is a Third Of (a number)?

S1-SA2-0241

Grade Level:

Class 3

Maths, Finance, Physics, AI

Definition

What is it?

Finding 'a third of' a number means dividing that number into three equal parts. It's like sharing something equally among three friends. You can also write 'a third of' as 1/3.

Simple Example

Quick Example

Imagine you have 15 ladoos, and you want to share them equally among your two siblings and yourself. To find a third of 15 ladoos, you would divide 15 by 3. Each person would get 5 ladoos.

Worked Example

Step-by-Step

Let's find a third of 27.

STEP 1: Understand that 'a third of' means dividing by 3.
---STEP 2: Write down the division problem: 27 ÷ 3.
---STEP 3: Recall your multiplication tables or perform the division.
---STEP 4: 3 multiplied by 9 equals 27.
---STEP 5: So, 27 divided by 3 is 9.

ANSWER: A third of 27 is 9.

Why It Matters

Understanding 'a third of' helps us in everyday sharing and calculations. In finance, it can help divide profits or expenses. In physics, it's used when calculating proportions, and even in AI, it can be used for splitting data for analysis or training models.

Common Mistakes

MISTAKE: Multiplying the number by 3 instead of dividing. For example, finding a third of 9 as 27. | CORRECTION: Remember 'a third of' means splitting into 3 equal parts, which requires division by 3.

MISTAKE: Confusing 'a third of' with 'one-half' or 'one-fourth'. For example, dividing by 2 or 4. | CORRECTION: 'A third' specifically refers to division by 3. Always check the fraction or wording carefully.

MISTAKE: Not being able to divide evenly and thinking the concept doesn't apply. For example, trying to find a third of 10 and getting stuck. | CORRECTION: While some numbers divide evenly, others will give a remainder or a decimal. The concept still applies; the answer might just not be a whole number.

Practice Questions

Try It Yourself

QUESTION: What is a third of 30? | ANSWER: 10

QUESTION: Your dad earned Rs. 600 from selling vegetables. He wants to save a third of it. How much money will he save? | ANSWER: Rs. 200

QUESTION: A cricket match has 36 overs. If the first bowler bowled a third of the total overs, and the second bowler bowled half of the remaining overs, how many overs did the second bowler bowl? | ANSWER: 12 overs

MCQ

Quick Quiz

Which operation is used to find a third of a number?

Multiplication by 3

Addition of 3

Division by 3

Subtraction of 3

The Correct Answer Is:

To find 'a third of' a number means to divide that number into three equal parts, which is done using division by 3. Multiplication, addition, or subtraction would give different results.

Real World Connection

In the Real World

When a family of three wants to split a bill equally at a restaurant, they find a third of the total amount. Or, if a farmer has 99 kg of wheat and wants to sell a third of it at the market, they calculate 99 ÷ 3 to know how much to take.

Key Vocabulary

Key Terms

FRACTION: A part of a whole | DIVIDE: To split into equal parts | NUMERATOR: The top number in a fraction (here, 1) | DENOMINATOR: The bottom number in a fraction (here, 3) | EQUAL PARTS: Parts that are the same size or amount

What's Next

What to Learn Next

Now that you understand finding 'a third of' a number, you can explore other fractions like 'a half of' or 'a fourth of'. These concepts build on the same idea of division and help you understand how to work with parts of a whole.