What is 4 × 5?

S1-SA1-0680

Grade Level:

Class 2

Maths, Computing, AI

Definition

What is it?

4 × 5 means adding the number 4, five times (4 + 4 + 4 + 4 + 4). It is a basic multiplication problem where you find the product of two numbers. This helps you quickly count groups of items.

Simple Example

Quick Example

Imagine you have 4 friends, and each friend gives you 5 toffees. To find the total number of toffees you have, you can multiply 4 × 5. This will tell you how many toffees you got in total.

Worked Example

Step-by-Step

Let's calculate 4 × 5 step-by-step:
1. Understand what 4 × 5 means: It means 4 groups of 5, or 5 groups of 4.
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2. Let's use repeated addition: We will add the number 5, four times.
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3. First addition: 5 + 5 = 10
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4. Second addition: 10 + 5 = 15
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5. Third addition: 15 + 5 = 20
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6. So, 4 × 5 = 20.
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Answer: 20

Why It Matters

Understanding basic multiplication like 4 × 5 is crucial for higher Maths, Computing, and even AI. In computing, it's used for array indexing and data processing. In AI, it forms the basis of matrix multiplications used in neural networks, helping systems like self-driving cars or voice assistants make decisions.

Common Mistakes

MISTAKE: Adding 4 and 5 (4 + 5 = 9) instead of multiplying. | CORRECTION: Remember that '×' means multiplication, which is repeated addition, not simple addition.

MISTAKE: Confusing 4 × 5 with 4 + 4 + 4 + 4 (adding 4 four times). | CORRECTION: 4 × 5 means 4 groups of 5 (5 + 5 + 5 + 5) or 5 groups of 4 (4 + 4 + 4 + 4 + 4). Count the number of times you are adding.

MISTAKE: Getting confused by the order (thinking 4 × 5 is different from 5 × 4). | CORRECTION: For multiplication, the order of numbers doesn't change the answer. 4 × 5 is the same as 5 × 4 (both are 20).

Practice Questions

Try It Yourself

QUESTION: A auto-rickshaw driver makes 4 trips in an hour, and each trip earns him 5 rupees. How much money does he earn in an hour from these trips? | ANSWER: 20 rupees

QUESTION: If you have 5 boxes, and each box contains 4 laddoos, how many laddoos do you have in total? | ANSWER: 20 laddoos

QUESTION: Your school playground has 4 rows of benches. Each row has 5 benches, and each bench can seat 2 students. How many students can sit in one row? (Hint: First find 4 × 5). | ANSWER: 10 students (4 rows x 5 benches = 20 benches, but the question asks for one row: 5 benches x 2 students/bench = 10 students)

MCQ

Quick Quiz

What is the result of 4 × 5?

The Correct Answer Is:

4 × 5 means adding 5 four times (5 + 5 + 5 + 5), which equals 20. Options A, B, and D are incorrect calculations.

Real World Connection

In the Real World

When you buy 4 packets of biscuits, and each packet costs 5 rupees, a shopkeeper quickly calculates 4 × 5 = 20 rupees using multiplication. This is similar to how billing systems at supermarkets or online shopping apps like Flipkart use multiplication to total your cart value.

Key Vocabulary

Key Terms

MULTIPLICATION: A way of adding the same number multiple times quickly. | PRODUCT: The answer you get when you multiply two or more numbers. | FACTORS: The numbers you multiply together to get a product. | REPEATED ADDITION: Adding the same number over and over.

What's Next

What to Learn Next

Great job mastering 4 × 5! Next, you should explore the full multiplication tables, like the 5-times table and 4-times table. This will help you multiply any numbers faster and build a strong foundation for division and fractions.