A number is divisible by 5 if its last digit is either a 0 or a 5. This simple rule, highlighted in the [YouTube video "Divisibility Rule for 5 | Math with Mr. J"](), makes checking for divisibility by 5 very easy.
Divisibility Rule Explained
The divisibility rule for 5 is straightforward and easy to remember:
- Check the last digit: Look at the ones place of the number.
- Zero or Five: If the digit is a 0 or a 5, the number is divisible by 5 without any remainder.
Examples of Numbers Divisible by 5
Here are some examples to illustrate the rule:
- 25: Ends in 5, so it's divisible by 5. (25 / 5 = 5)
- 100: Ends in 0, so it's divisible by 5. (100 / 5 = 20)
- 345: Ends in 5, so it's divisible by 5. (345 / 5 = 69)
- 1280: Ends in 0, so it's divisible by 5. (1280 / 5 = 256)
Examples of Numbers Not Divisible by 5
Here are examples of numbers that are not divisible by 5:
- 16: Ends in 6, not a 0 or 5, so it's not divisible by 5.
- 23: Ends in 3, not a 0 or 5, so it's not divisible by 5.
- 102: Ends in 2, not a 0 or 5, so it's not divisible by 5.
- 557: Ends in 7, not a 0 or 5, so it's not divisible by 5.
Why This Rule Works
The divisibility rule for 5 works because our number system is based on powers of 10. All numbers can be represented as a sum of multiples of 10 plus a single digit. Since any multiple of 10 is always divisible by 5, whether a number is divisible by 5 depends only on the last digit's divisibility by 5.
Practical Use
This divisibility rule is a quick and easy way to determine whether a number can be divided evenly by 5. It's commonly taught in elementary school and is a helpful tool for quick mental math.
