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What is Divisibility by 5?
Grade Level:
Class 4
Maths, Computing, AI
Definition
What is it?
Divisibility by 5 means that when you divide a number by 5, there is no remainder left. In simpler words, a number is divisible by 5 if it can be shared equally among 5 groups.
Simple Example
Quick Example
Imagine you have 25 ladoos to share equally among 5 friends. Since each friend gets exactly 5 ladoos with none left over, 25 is divisible by 5. If you had 27 ladoos, you couldn't share them equally, so 27 is not divisible by 5.
Worked Example
Step-by-Step
Let's check if the number 70 is divisible by 5.
1. Look at the last digit of the number 70.
---2. The last digit is 0.
---3. The rule for divisibility by 5 says that if a number ends in 0 or 5, it is divisible by 5.
---4. Since 70 ends in 0, it follows the rule.
---5. We can also do the actual division: 70 ÷ 5 = 14.
---6. The remainder is 0.
---So, 70 is divisible by 5.
Why It Matters
Understanding divisibility rules helps you quickly solve problems in Maths, which is super useful in Computing for writing efficient code. In AI, these basic number sense skills are foundational for understanding algorithms. Careers like data analyst or software developer use these concepts daily for logical problem-solving.
Common Mistakes
MISTAKE: Thinking any number with a 5 in it (like 51 or 152) is divisible by 5. | CORRECTION: Only the *last digit* matters. It must be a 0 or a 5.
MISTAKE: Confusing divisibility by 5 with divisibility by 2 or 10. | CORRECTION: Divisibility by 2 requires the last digit to be even (0, 2, 4, 6, 8). Divisibility by 10 requires the last digit to be 0. Divisibility by 5 specifically requires the last digit to be 0 or 5.
MISTAKE: Not checking the remainder when actually dividing. | CORRECTION: If you perform division, always ensure the remainder is exactly zero for the number to be truly divisible.
Practice Questions
Try It Yourself
QUESTION: Is 45 divisible by 5? | ANSWER: Yes
QUESTION: Which of these numbers is NOT divisible by 5: 30, 58, 105, 250? | ANSWER: 58
QUESTION: A shopkeeper has 123 pens. Can he pack them into bundles of 5 pens each without any pens left over? Explain why. | ANSWER: No. The number 123 ends in 3, not 0 or 5, so it is not divisible by 5. There will be 3 pens left over.
MCQ
Quick Quiz
Which of the following numbers is divisible by 5?
12
34
50
71
The Correct Answer Is:
C
A number is divisible by 5 if its last digit is 0 or 5. Out of the given options, only 50 has 0 as its last digit, making it divisible by 5.
Real World Connection
In the Real World
Imagine you're buying snacks at a local 'kirana' store. Many items, like biscuits or chocolates, are often priced in multiples of ₹5 (e.g., ₹10, ₹15, ₹20). Knowing divisibility by 5 helps you quickly calculate if your total bill will be an exact multiple of 5 rupees, or if you'll need smaller change.
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 when the divisor does not divide the dividend exactly. | MULTIPLE: A number that can be divided by another number without a remainder. | DIGIT: A single symbol used to make numerals.
What's Next
What to Learn Next
Great job learning divisibility by 5! Next, you can explore 'Divisibility by 10'. It builds on what you've learned here, as numbers divisible by 10 also follow a simple last-digit rule, making calculations even faster.
