Multiply a 2-digit by a 1-digit number
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
Check your knowledge of multiplying a 2-digit by a 1-digit number in this quiz.
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.
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.
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.
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
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:
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.
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 Guardians: Defenders of Mathematica to learn more and sharpen your skills on this topic.
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