Or

Author:
Nathaniel Zapien

CCSS.MATH.CONTENT.3.OA.D.9 Identify arithmetic patterns (including patterns in the addition table or multiplication table), and explain them using properties of operations.

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Tutorial

Today we'll be learning how to identify and use arithmetic patterns to multiply.

We'll learn about several different strategies to multiply by 9.

Take a look at the table below. Notice the pattern that occurs with the product of a multiple of 9. Think how you can use this information to help you multiply or check your answer.

The number 9 truly is a special number.

Now take that information and take a look at the poster on this page called "The 9s Trick"

Noticing these patterns lets us do a number of different.

For Instance:

When counting by 9s, we can also count by 10s and subtract 1.

This is called the 10 More, 1 Less strategy.

9×n = (10×n) – (1×n)

Jump into your math notebook and answer this question!

Why is it important to know several strategies for solving larger multiplication facts?