3-3 Use Arrays to Multiply by 1-Digit Numbers

An Array is a way to represent multiplication because it has an equal number of objects in each row.

Partial Products - A partial product is a product of two numbers obtained when we break the numbers into parts, multiply the parts separately and then add them together. 

For example, suppose we have to find the product of 8 and 25. 

We first expand 25 as 20 + 5.

Now we find the product of 

8 x 20 = 160

8 x 5 = 40

So we can add 160 + 40 = 200 and we know that 8 x 25 = 200.

You'll be using the area model in the next lesson with rectangles to help you see this.

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