Divisibility and Divisibility Rules
🎬 Video: Rules of Divisibility Explained
What Does Divisible Mean? (0:01)
🌟 Definition of Divisibility:
When you divide a number and there’s no remainder, the number is divisible by the other.
🍌 Example 1:
$ 9 \div 2 = 4 \text{ R }1$
The remainder is 1, so 9 is not divisible by 2.
🍌 Example 2:
$ 9 \div 3 = 3$
There’s no remainder, so 9 is divisible by 3.
Divisibility Rules for 2, 4, and 8 (0:45)
Divisibility rules help you quickly check if a number is divisible without doing the full division.
💡 Divisible by 2:
Rule: Look at the last digit. If it’s 0, 2, 4, 6, or 8, the number is divisible by 2.
Example: Is 26 divisible by 2?
- 26 ends in 6, which is even.
- So, 26 is divisible by 2.
💡 Divisible by 4:
Rule: Look at the last two digits. If those digits make a number divisible by 4, the whole number is divisible by 4.
Example: Is 328 divisible by 4?
- The last two digits of 328 are 28.
- 28 is divisible by 4, so 328 is divisible by 4.
💡Divisible by 8:
Rule: Look at the last three digits. If that number is divisible by 8, then the whole number is.
Example:
- The last three digits of 6160 are 160.
- 160 is divisible by 8, so 6160 is divisible by 8.
Divisibility Rules for 3, 6, and 9 (1:34)
💡Divisible by 3:
Rule: Add all the digits. If the sum is divisible by 3, then the whole number is divisible by 3.
Example: Is 543 divisible by 3?
- Adding all digits: 5 + 4 + 3 = 12
- 12 is divisible by 3, so 543 is divisible by 3.
💡 Divisible by 9:
Rule: Add all the digits. If the sum is divisible by 9, then the number is divisible by 9.
Example: Is 198 divisible by 9?
- Adding all digits: 1 + 9 + 8 = 18
- 18 is divisible by 9, so 198 is divisible by 9.
💡Divisible by 6:
Rule: Check if the number is divisible by both 2 and 3. If it passes both checks, then the number is divisible by 6.
Example: Is 402 divisible by 6?
- The last digit is 2, so 402 is divisible by 2.
- The sum of all digits is 4 + 0 + 2 = 6.
- 6 is divisible by 3, so 402 is divisible by 3.
- Since 402 is divisible by 2 and 3, 402 is divisible by 6.
Divisibility Rules for 5 and 10 (2:52)
💡Divisible by 5:
Rule: A number is divisible by 5 if its last digit is 0 or 5.
Example: Is 415 divisible by 5?
- The last digit is 5, so 415 is divisible by 5.
💡Divisible by 10:
Rule: A number is divisible by 10 if its last digit is 0.
Example: Is 320 divisible by 10?
- The last digit is 0, so 320 is divisible by 10.
📂 Flashcards: Divisibility Rules (2 to 9)
🍪 Quiz: Test Your Divisibility Skills
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