Even or odd: arithmetic rules

key notes:

🔢 What Are Even and Odd Numbers?

Type	Ends With	Examples	Can it be split into 2 equal groups?
Even	0, 2, 4, 6, 8	12, 28, 40, 102	✅ Yes – No remainder
Odd	1, 3, 5, 7, 9	13, 29, 47, 101	❌ No – 1 leftover

🎯 Tip: Look at the ones digit to decide if a number is even or odd!

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➕Rules for Addition and Subtraction

Rule	Result	Example	Answer
Even + Even	Even	4 + 6	10 (Even)
Odd + Odd	Even	3 + 5	8 (Even)
Even + Odd / Odd + Even	Odd	2 + 3 or 5 + 4	5 / 9 (Odd)
Even – Even	Even	10 − 2	8 (Even)
Odd – Odd	Even	7 − 3	4 (Even)
Even – Odd / Odd – Even	Odd	8 − 3 or 7 − 2	5 (Odd)

🧠 Rule of Thumb:

• Same types (even+even / odd+odd) = Even
• Different types (even+odd) = Odd

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✖️ Rules for Multiplication

Rule	Result	Example	Answer
Even × Even	Even	2 × 6	12 (Even)
Even × Odd / Odd × Even	Even	2 × 5 or 7 × 4	10 / 28 (Even)
Odd × Odd	Odd	3 × 5	15 (Odd)

🔍 Why?

• Even numbers have 2 as a factor, so product becomes even.
• Odd × Odd = Odd, only when no even number is involved.

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🔄 Rules for Division (Simple Cases)

• Even ÷ 2 → Even or Odd (Depends on the number)
  Example: 8 ÷ 2 = 4 (Even), 6 ÷ 2 = 3 (Odd)
• Odd ÷ 2 → Not whole number
  Example: 5 ÷ 2 = 2.5 ❌ (Not even or odd)

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📝 Practice Time!

👉 Decide if the result is Even or Odd:

1. 8 + 6 = _______
2. 9 + 5 = _______
3. 7 × 3 = _______
4. 4 × 5 = _______
5. 10 − 4 = _______
6. 27 + 16 = _______
7. 11 × 11 = _______

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🧠 Quick Recap with Logic

• Even numbers = multiples of 2
• Odd numbers = 1 more or 1 less than a multiple of 2
• Multiplying with an even always gives even
• Adding same type gives even, different types gives odd

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🎲 Real-Life Fun

🚗 Counting wheels on cars (4), bikes (2), autos (3)… what are they?

🎮 Number of players in a game – even teams?

🍎 Sharing apples between friends – can they be shared equally?

Learn with an example

Let’s practice!