What is Thirty-One?

S0-SA1-1016

Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

Thirty-One is a natural number that comes after 30 and before 32. It is written as '31' using two digits: 3 in the tens place and 1 in the ones place.

Simple Example

Quick Example

Imagine you have 30 laddoos, and your friend gives you one more. Now you have 31 laddoos in total! This is how we count past thirty.

Worked Example

Step-by-Step

Let's count to 31 using groups of ten.

Step 1: Start with three groups of ten items. If you have 10 pens, then another 10 pens, and then another 10 pens, you have 3 groups of 10.
---Step 2: Calculate the total from these groups. 10 + 10 + 10 = 30 pens.
---Step 3: Now, add one more pen to your collection.
---Step 4: Count the total: 30 pens + 1 pen = 31 pens.
---Answer: So, 31 is three tens and one one.

Why It Matters

Understanding numbers like 31 is fundamental for all mathematics, from basic arithmetic to advanced algebra. It's used by shopkeepers to count items, by engineers to measure, and by coders in programming. Mastering numbers helps you count money, manage time, and understand data in almost every career.

Common Mistakes

MISTAKE: Writing '301' instead of '31' when hearing 'thirty-one'. | CORRECTION: Remember 'thirty' means three tens (3 in the tens place) and 'one' means one unit (1 in the ones place), so it's 31.

MISTAKE: Confusing 'thirty-one' with 'thirteen'. | CORRECTION: 'Thirty-one' is 31 (three tens and one unit), while 'thirteen' is 13 (one ten and three units). The order of digits matters a lot!

MISTAKE: Forgetting that 31 is an odd number. | CORRECTION: An odd number cannot be divided into two equal whole numbers. 31 leaves a remainder of 1 when divided by 2, making it odd.

Practice Questions

Try It Yourself

QUESTION: If you have 30 cricket balls and you buy 1 more, how many balls do you have? | ANSWER: 31

QUESTION: Write the number that comes just before 32. | ANSWER: 31

QUESTION: Your mom gives you three ₹10 notes and one ₹1 coin. How much money do you have in total? | ANSWER: ₹31

MCQ

Quick Quiz

Which of these represents 'thirty-one'?

301

3 + 1

The Correct Answer Is:

Option C, 31, correctly represents 'thirty-one' with 3 in the tens place and 1 in the ones place. Options A, B, and D are incorrect numbers or operations.

Real World Connection

In the Real World

When you check the scores in a cricket match, a batsman might have scored 31 runs. Or, if you're buying snacks at the school canteen, the total bill might come up to ₹31. Many buses or train coaches might have 31 seats in a row.

Key Vocabulary

Key Terms

DIGIT: A single symbol used to write numbers (0, 1, 2, etc.) | PLACE VALUE: The value of a digit based on its position in a number | NATURAL NUMBER: A whole number greater than 0 (1, 2, 3, ...) | ODD NUMBER: A whole number that cannot be divided exactly by 2

What's Next

What to Learn Next

Now that you understand 31, you can explore other numbers like 32, 33, and beyond. You'll also learn about counting by tens, which helps you quickly understand numbers up to 100 and even larger!