NZ Level 3
Multiply a single digit number by a three digit number using an area model
Lesson

When we multiply a one-digit number by a three-digit number, there's a great way of using the area of rectangles to help us.

Remember, to find the area of a rectangle, we use the formula:

$\text{Area of a rectangle }=\text{length }\times\text{width }$Area of a rectangle =length ×width

Now take a look at the video to see how you can break your multiplication problem up into smaller steps, using rectangles.

Remember!
• We can break up large rectangles into smaller rectangles and find the areas to solve large multiplication questions.
• One way to break up three-digit numbers is to use the hundreds, tens and unit values.

#### Worked Examples

##### Question 1

We want to find $344\times3$344×3 using the area model.

1. Find the area of the first rectangle.

2. Find the area of the second rectangle.

3. Find the area of the third rectangle.

4. What is the total area of all three rectangles?

5. So what is $344\times3$344×3?

##### question 2

We want to use the area model to find $225\times4$225×4.

1. Fill in the areas of each rectangle.

 $200$200 $20$20 $5$5 $4$4 $\editable{}$ $\editable{}$ $\editable{}$
2. What is the total area of all three rectangles?

3. So what is $225\times4$225×4?

##### question 3

We want to use the area model to find $907\times2$907×2.

1. Fill in the areas of each rectangle.

 $900$900 $7$7 $2$2 $\editable{}$ $\editable{}$
2. What is the total area of both rectangles?

3. So what is $907\times2$907×2?

### Outcomes

#### NA3-6

Record and interpret additive and simple multiplicative strategies, using words, diagrams, and symbols, with an understanding of equality