What is Forty?

S0-SA1-0585

Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

Forty is a natural number that comes after thirty-nine (39) and before forty-one (41). In mathematics, it is represented by the digits '4' and '0' together, making it a two-digit number.

Simple Example

Quick Example

Imagine you have 39 cricket stickers, and your friend gives you one more. Now, you have 40 cricket stickers in total! It's also how many runs a batsman needs to score to reach a 'forty' in an inning.

Worked Example

Step-by-Step

Let's say your school library has 35 storybooks. Your principal decides to add 5 more new storybooks.
---Step 1: Identify the initial number of storybooks. Initial books = 35.
---Step 2: Identify the number of new storybooks added. Added books = 5.
---Step 3: To find the total, add the new books to the initial books. Total books = Initial books + Added books.
---Step 4: Perform the addition. Total books = 35 + 5.
---Step 5: Calculate the sum. 35 + 5 = 40.
---Answer: The school library now has 40 storybooks.

Why It Matters

Understanding numbers like forty is fundamental to counting, measuring, and calculations in everyday life. It's crucial for careers like banking, where you handle money, or in engineering, where you measure materials. Even a shopkeeper uses numbers like forty to count items or give change.

Common Mistakes

MISTAKE: Writing 'forty' as 'fourty' | CORRECTION: The correct spelling is 'forty', without the 'u' after 'o'.

MISTAKE: Confusing forty (40) with fourteen (14) | CORRECTION: Forty has a 'ty' sound at the end and is a much larger number, while fourteen has a 'teen' sound and is smaller.

MISTAKE: Thinking 40 is a prime number | CORRECTION: A prime number only has two factors (1 and itself). Forty has many factors (1, 2, 4, 5, 8, 10, 20, 40), so it is a composite number.

Practice Questions

Try It Yourself

QUESTION: If you have 20 rupees and your friend gives you 20 more rupees, how much money do you have in total? | ANSWER: 40 rupees

QUESTION: A bus has 45 seats. If 5 seats are empty, how many passengers are currently on the bus? | ANSWER: 40 passengers

QUESTION: Your favourite mobile game requires 100 points to unlock a new level. If you currently have 60 points, how many more points do you need to reach the new level? | ANSWER: 40 points

MCQ

Quick Quiz

Which of these represents the number forty?

forty-one

The Correct Answer Is:

Option B, '40', is the correct numerical representation of forty. Options A, C, and D represent different numbers.

Real World Connection

In the Real World

In India, you might see '40' in many places. For example, a chai-wala might sell a cup of chai for 40 rupees. Your mobile data plan might give you 40 GB of data per month. Or, a speed limit sign on a road could show '40 km/h' meaning you shouldn't drive faster than 40 kilometres per hour.

Key Vocabulary

Key Terms

NATURAL NUMBER: A counting number starting from 1 (1, 2, 3, ...)| DIGITS: The symbols used to write numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)| COMPOSITE NUMBER: A number that has more than two factors (1 and itself)

What's Next

What to Learn Next

Now that you understand what forty is, you can learn about other numbers and how they fit into our number system. Next, you can explore concepts like place value for two-digit numbers or learn about multiples of numbers like forty.