What is Divisibility by 8?

S1-SA1-0165

Grade Level:

Class 5

Maths, Computing, AI

Definition

What is it?

Divisibility by 8 means that when you divide a number by 8, the remainder is 0. In simpler words, a number is divisible by 8 if it can be split into exactly 8 equal parts without anything left over.

Simple Example

Quick Example

Imagine you have 24 laddoos. Can you divide them equally among 8 friends, so each friend gets the same number of laddoos with none left? Yes, each friend gets 3 laddoos (24 ÷ 8 = 3). So, 24 is divisible by 8.

Worked Example

Step-by-Step

Let's check if the number 512 is divisible by 8.
1. Look at the last three digits of the number. For 512, the last three digits are 512 itself.
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2. Divide these last three digits by 8. So, we need to calculate 512 ÷ 8.
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3. Perform the division: 512 ÷ 8 = 64.
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4. Since the remainder is 0 (512 divides exactly by 8), the number 512 is divisible by 8.
Answer: Yes, 512 is divisible by 8.

Why It Matters

Understanding divisibility rules helps you quickly solve problems in Maths without needing a calculator. In Computing, this concept is used in data storage and memory management. It's also fundamental for careers like software development and data analysis, where efficient number handling is key.

Common Mistakes

MISTAKE: Checking only the last digit or last two digits for divisibility by 8. | CORRECTION: For divisibility by 8, you MUST check the last THREE digits of the number.

MISTAKE: Thinking that if a number is divisible by 4, it must also be divisible by 8. | CORRECTION: This is not always true. For example, 12 is divisible by 4 but not by 8. Always check the last three digits for divisibility by 8.

MISTAKE: Confusing the rule for 8 with the rule for 2 (last digit even) or 4 (last two digits divisible by 4). | CORRECTION: Remember the unique rule for 8: the number formed by its last three digits must be divisible by 8.

Practice Questions

Try It Yourself

QUESTION: Is 160 divisible by 8? | ANSWER: Yes

QUESTION: A bus carries 8 passengers per trip. Can 344 passengers be transported without anyone being left behind or any empty seats? | ANSWER: Yes, because 344 is divisible by 8.

QUESTION: Find the smallest 3-digit number that is divisible by 8 and ends with a 6. | ANSWER: 136

MCQ

Quick Quiz

Which of these numbers is NOT divisible by 8?

240

568

724

800

The Correct Answer Is:

For 724, the last three digits form the number 724. When you divide 724 by 8, you get 90 with a remainder of 4. So, 724 is not divisible by 8. The other options (240, 568, 800) are all divisible by 8.

Real World Connection

In the Real World

When you download a large file on your phone or computer, its size is often measured in megabytes (MB) or gigabytes (GB). These units are based on powers of 2 (which includes 8, since 8 is 2x2x2). Understanding divisibility by 8 can help you grasp how data storage works and why certain file sizes are common.

Key Vocabulary

Key Terms

DIVISIBILITY: The ability of one number to be divided by another number without a remainder. | REMAINDER: The amount left over after a division. | QUOTIENT: The result obtained when one number is divided by another. | MULTIPLE: A number that can be divided by another number without a remainder (e.g., 16 is a multiple of 8).

What's Next

What to Learn Next

Great job learning about divisibility by 8! Next, you can explore divisibility by 9. This will help you understand more about number properties and make you even faster at mental math!