Even / Odd

What Are Even and Odd Numbers?

• Even and Odd are words we use to describe how numbers can be divided.
• Think of it as the "Buddy System." * Every number is either even or odd, depending on whether every "player" has a partner or if someone is left out.

The Buddy Rule The easiest way to tell the difference is to try to put things in pairs (groups of 2):

1. Even Numbers (Everyone has a Buddy)

• If you can group all objects into pairs with none left over, the number is Even.
• Even numbers are "fair"—everyone has a friend to play with!
• Even Numbers end in: 0, 2, 4, 6, or 8.

2. Odd Numbers (Someone is Alone)

• If you group objects into pairs and there is one left over, the number is Odd.
• Odd numbers have a "lonely" one who doesn't have a partner.
• Odd Numbers end in: 1, 3, 5, 7, or 9.

The Secret Trick: Look at the Last Digit Even when numbers get big, you only need to look at the very last number (the ones place) to know if it is even or odd:

• 14: Ends in 4. Even!
• 21: Ends in 1. Odd!
• 30: Ends in 0. Even!
• 57: Ends in 7. Odd!

Why Do We Learn This?

• Division: It is the first step in learning how to split things in half.
• Patterns: It helps you see patterns in numbers (it goes: Odd, Even, Odd, Even...).
• Mental Math: Knowing your "pairs" makes adding and subtracting much faster.

Lesson Summary

• Even: Every number has a partner (ends in 0, 2, 4, 6, 8).
• Odd: One number is left out (ends in 1, 3, 5, 7, 9).
• Use the "Buddy System" to check!