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Here are some tips for Odd or Even Theory, which aligns with Florida state standards:

**Odd or Even Theory**

To review odd and even numbers, see here.

Addition | Subtraction | Multiplication |
---|---|---|

even + even = even | even - even = even | even * even = even |

even + odd = odd | even - odd = odd | even * odd = even |

odd + even = odd | odd - even = odd | odd * even = even |

odd + odd = even | odd - odd = even | odd * odd = odd |

Here is an easier way to think about this.

- for addition and subtraction, if the numbers are both even or both odd, the answer is always even.
- for multiplication,
*any*number(s) multiplied by an even number is even.

**Example 1:** Addition and Subtraction of 3 numbers

Is the resulting number odd or even?

25160 + 35516 - 31337Rewrite the equation in terms of odd or even, then solve.

The resulting answer is odd.

25160 + 35516 - 31337 even + even - odd even + even - odd Solve the first part even - odd even + even = even odd even - odd = odd

**Example 2:** Addition and multiplication of 3 numbers

Is the resulting number odd or even?

18425 × 29531 + 15309

Rewrite the equation in terms of odd or even, then solve.

The resulting answer is even.

18425 × 29531 + 15309 odd × odd + odd odd × odd + odd Solve the first part odd + odd odd × odd = odd even odd + odd = even

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