Divisibility Rules: Is Every Multiple of 6 Also a Multiple of 3?

Divisibility Properties with Factor Relationships

Will a number divisible by 6 necessarily be divisible by 3?

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Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Will a number divisible by 6 necessarily be divisible by 3?

2

Step-by-step solution

To determine whether a number divisible by 6 is necessarily divisible by 3, we need to understand the properties of divisibility for the numbers involved.

Let's analyze the problem step by step:

  • Step 1: Restate the Problem
    We need to find out if any number that is divisible by 6 is also divisible by 3.
  • Step 2: Identify Key Information and Variables
    - A number is divisible by 6 if it can be expressed as k×6 k \times 6 for any integer k k .
    - We want to check if such a number is also divisible by 3, meaning it can also be expressed as m×3 m \times 3 for some integer m m .
  • Step 3: Relevant Theorems
    - A number is divisible by 6 if it is divisible by both 2 and 3.
  • Step 4: Choose Approach
    We'll use the divisibility rules for numbers to deduce if a number divisible by 6 must be divisible by 3.
  • Step 5: Steps for Solution
    1. Given a number is divisible by 6, it is expressed as a multiple of 6: n=k×6 n = k \times 6 .
    2. Since 6 can be factored into 2×3 2 \times 3 , a number divisible by 6 is also divisible by 3.
    3. Therefore, n=k×6=k×(2×3)=(k×2)×3 n = k \times 6 = k \times (2 \times 3) = (k \times 2) \times 3 , making it divisible by 3.
  • Step 6: Assumptions
    We assume the integer k k is any integer and does not affect the general proof.
  • Step 7: Conclusion
    Every number divisible by 6 is necessarily divisible by both 2 and 3, due to the factorization properties of numbers. Thus, by the rules of divisibility, a number divisible by 6 is necessarily divisible by 3.

Therefore, the answer to the problem is Yes.

3

Final Answer

Yes

Key Points to Remember

Essential concepts to master this topic
  • Rule: Numbers divisible by 6 are divisible by its factors 2 and 3
  • Technique: Factor 6 as 2 × 3, so 18 ÷ 6 means 18 ÷ (2 × 3)
  • Check: Test with examples: 12 ÷ 6 = 2, and 12 ÷ 3 = 4 ✓

Common Mistakes

Avoid these frequent errors
  • Thinking larger divisors don't guarantee smaller divisors
    Don't assume that just because 6 is bigger than 3, divisibility by 6 doesn't guarantee divisibility by 3 = wrong reasoning! This ignores how factors work. Always remember that if a number divides evenly by a composite number, it also divides by all factors of that number.

Practice Quiz

Test your knowledge with interactive questions

Will a number divisible by 6 necessarily be divisible by 3?

FAQ

Everything you need to know about this question

Why does divisibility by 6 always mean divisibility by 3?

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Because 6 = 2 × 3! When a number is divisible by 6, it's really divisible by the product 2 × 3, which means it must be divisible by both factors separately.

Does this work with other numbers too?

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Yes! If a number is divisible by any composite number, it's automatically divisible by all the factors of that number. For example, divisibility by 12 guarantees divisibility by 1, 2, 3, 4, and 6.

Can I find a number divisible by 6 but not by 3?

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No, it's impossible! Every multiple of 6 contains 3 as a factor. Try any multiple: 6, 12, 18, 24, 30 - they're all divisible by 3.

How can I remember this rule?

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Think of it like ingredient lists! If something contains '6', it automatically contains all the 'ingredients' that make 6: both 2 and 3.

What's the difference between factors and multiples?

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Factors are numbers that divide evenly into your number (3 is a factor of 6). Multiples are numbers your number divides into evenly (6, 12, 18 are multiples of 3).

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