Multiply a two digit number by a small single digit number using an area model

Multiplying a single digit number by a two digit number

When we solve a problem such as $4\times12$4×12, we can use some different methods to help us. Here, we look at how we can use the area of rectangles to solve these problems.

 

The area of rectangles

When solving $4\times12$4×12,we can calculate the area of a rectangle that has sides that measure $4$4 and $12$12. To break this down into smaller problems, we can think of this as the area of two rectangles added together.

Let's take a look at how we do this in Video 1.

Sometimes, we are asked to calculate our answer, without drawing rectangles. When we do this, we can imagine the rectangles and calculate our separate answers, then add them together to get our total. For example, we could solve $5\times15$5×15 in a table like this:

x	5
10
5

 

Sometimes we can use information that we already know to help us break our multiplication into smaller problems. Using things such as multiplying by $10$10, times tables, or other multiplication facts we know, can help use solve multiplication questions. Let's have a look at some examples now.

 

 

Worked examples

Question 1

Question 2

Question 3