Even and Odd numbers

Topic Notes

In this lesson, we will learn:

  • Every whole number is either even or odd, and they alternate one after the other (even, odd, even, odd)
  • Even numbers end in the digits: 0, 2, 4, 6, or 8
  • Odd numbers end in the digits: 1, 3, 5, 7, or 9
  • Even numbers will pair up while odd numbers will not pair up

Notes:

  • To find out if a number is even or odd, you look at the ones digit.
    • Odd and even numbers alternate (even-odd-even-odd)
    • Even numbers end in 0, 2, 4, 6, or 8
    • Odd numbers end in 1, 3, 5, 7, or 9

Ex. showing even and odd numbers on a number line

Even and Odd Numbers

  • You could also think of even and odd numbers as skip-counting by 2s:
    • Even numbers: start at 0 and add 2 each time
      • 0, 2, 4, 6, 8, 10, 12, 14, …
    • Odd numbers: start at 1 and add 2 each time
      • 1, 3, 5, 7, 9, 11, 13, 15, …
  • Another way to think of it is that:
    • Even numbers will pair up
    • And odd numbers will not pair up

Ex. pairs of circles have a box around them, left over ones are alone outside the boxes

Even and Odd Numbers