What is Adding One-Digit Numbers?

S1-SA1-0042

Grade Level:

Class 1

Maths, Computing, AI

Definition

What is it?

Adding one-digit numbers means combining two single-digit numbers (0 to 9) to find their total sum. It helps us count how many things we have when we put groups together.

Simple Example

Quick Example

Imagine you have 3 ladoos and your friend gives you 2 more ladoos. To find out how many ladoos you have in total, you add 3 and 2. The answer is 5 ladoos.

Worked Example

Step-by-Step

Let's add 4 and 5.

Step 1: Start with the first number, 4. You can think of having 4 pencils.
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Step 2: Now, add the second number, 5. This means adding 5 more pencils to your existing 4.
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Step 3: Count all the pencils together. You have 1, 2, 3, 4 (your original pencils) and then 5, 6, 7, 8, 9 (after adding the new ones).
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Step 4: The total count is 9.

So, 4 + 5 = 9.

Why It Matters

Adding numbers is a basic skill needed everywhere! In computing, it's how computers do calculations, from simple sums to complex AI algorithms. Future data scientists and software engineers use this fundamental idea every day to build apps, analyze data, and create smart systems.

Common Mistakes

MISTAKE: Counting incorrectly when using fingers or objects. For example, counting 1, 2, 3, 4, then starting again from 1 for the second number. | CORRECTION: Always continue counting from the first number's value. If you have 4, then add 3, you count: 4... 5, 6, 7.

MISTAKE: Confusing addition with subtraction. For example, thinking 5 + 2 is 3. | CORRECTION: Remember that addition always means combining things and getting a larger total (unless adding zero). Subtraction means taking away.

MISTAKE: Forgetting that adding zero doesn't change the number. For example, thinking 7 + 0 is 0. | CORRECTION: Any number plus zero is the number itself. If you have 7 chocolates and add 0 more, you still have 7.

Practice Questions

Try It Yourself

QUESTION: You bought 6 bananas and then 3 more. How many bananas do you have in total? | ANSWER: 9

QUESTION: What is the sum of 8 and 1? | ANSWER: 9

QUESTION: A small auto-rickshaw has 3 passengers. At the next stop, 4 more passengers get in. How many passengers are there now? | ANSWER: 7

MCQ

Quick Quiz

Which of these sums is equal to 7?

2 + 4

5 + 3

6 + 1

3 + 3

The Correct Answer Is:

6 + 1 equals 7. Option A (2+4=6), Option B (5+3=8), and Option D (3+3=6) are all incorrect sums.

Real World Connection

In the Real World

When you use UPI to pay for your chai and samosa, the app adds the price of your chai and the samosa to show you the total bill. Even simple calculators in your mobile phone or the billing system at a grocery store use addition to give you the final amount.

Key Vocabulary

Key Terms

ADDITION: The process of combining numbers to find their sum | SUM: The total result obtained by adding two or more numbers | ONE-DIGIT NUMBER: A whole number from 0 to 9 | TOTAL: The complete amount or number of something

What's Next

What to Learn Next

Great job with one-digit addition! Next, you can learn about 'Adding Two-Digit Numbers'. This will build on what you've learned here and help you solve bigger and more complex math problems quickly.