Multiply a 2-digit by a 1-digit number

Learning focus

Learn how to multiply a 2-digit number by a 1-digit number.

This lesson includes:

  • one catch-up quiz
  • one learning summary
  • one video

Quiz

Check your knowledge of multiplying a 2-digit by a 1-digit number in this quiz.

Learn

When multiplying a 2-digit number by a 1-digit number you can use both mental and written methods.

Let's take a look at an example of solving a multiplication problem in your head. Before you press play have a think about how you would work out 19 x 5 ?

Mental method for multiplication

You can do this by breaking down a number. Let's think about an example:

What is 6 x 40?

6 x 40 is equal to 6 x 4 x 10

Let’s focus on answering 6 x 4 first.

6 x 4 = 24

Now you can multiply 24 by 10. When you multiply by 10, all the digits move one space to the left and a zero is placed in the ones column to represent to number increasing in value.

24 x 10 = 240

Written method for multiplication

Sometimes it might be easier to use a written method to work out a 2-digit by a 1-digit multiplication.

We call this method short multiplication.

Example 1:

What is 48 x 6?

When you set out short multiplication, it is important to make sure the place value of the digits are in the correct place.

Put the 4 in the tens column and the 8 in the ones column.

Like this:

 

Step 1

Just like when you solve column addition and subtraction, you start with the digits in the ones.

8 x 6 = 48

Since 48 is 4 tens and 8 ones, you have to remember to keep the place values in the correct column. The 8 stays in the ones column, while you carry the 4 into the tens column.

 

Step 2

Time to work out 40 x 6 now.

40 x 6 = 240

But you can’t forget about the 4 tens that you carried over - you need to remember to add that on to the answer.

240 + 40 = 280

Again, make sure everything is in the correct place value column.

48 x 6 = 288

 

Example 2:

Beverley ordered 8 packets of balloons. Each packet contained 52 balloons. How many balloons has she got in total?

The equation we are working out is:

52 x 8

First, set the multiplication out correctly:

 

Step 1

Now the multiplication is set out correctly, you can solve the multiplication in the ones column.

2 x 8 = 16

 

Remember to carry the 1 into the tens column.

Step 2

Now it's time to work out 50 x 8

50 x 8 = 400

Don’t forget about the ten you carried over: 400 + 10 = 410.

52 x 8 = 416

Beverley now has 416 balloons.

 

Play

Play Guardians: Defenders of Mathematica to learn more and sharpen your skills on this topic.

Guardians: Defenders of Mathematica

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