Improve Your Skills When Adding and Subtracting Large Numbers

In this activity, we are going to practise adding and subtracting numbers with at least four digits.

The column method is an efficient method for adding and subtracting large numbers, so this is what we are going to use.

We will be exchanging/carrying in some questions - sometimes more than once!

Top Tips:

Write each question out clearly - it can be useful to use squared paper if you are writing out the questions.

Check the digits are in the correct order (it is easy to muddle them up!)

Make sure each digit is in the correct column.

Start at the ones and work towards the left-hand column.

We could use the inverse operation to check our answers! 

Example

 Add together 2,374 + 3,345 

We set out the question as shown in the example above.

Each digit must go in the correct column as shown.

We then add the columns together starting with the ones column.

The ones: 4 + 5 = 9  We put the 9 in the ones column.

The tens: 7 + 4 = 11 This is actually 70 + 40 = 110

We put 1 (10) in the tens column and carry 1 (100) over to under the hundreds column.

The hundreds: 3 + 3 = 6 + the carried 1 = 7 (300 + 300 = 600 + 100 = 700)

Finally, the thousands:  2 + 3 = 5 (2,000 + 3,000 = 5,000)

Have another read through the example if you need to!

Now let's have a look at a subtraction question:

6,574 -  3,356 = 

We write the number we are subtracting below the starting number.

The ones:  4 - 6 = 

We can't subtract 6 from 4 (we mustn't swap around and subtract 4 from 6)

We need to exchange one 10 and put it into the ones column.

Now we have 14 - 6 which we can do = 8

The tens: As we have taken ten from the ten column we need to adjust this column.  The 7 (70) becomes 6 (60)

6 - 5 = 1 (60 - 50 = 10)

The hundreds: 5 - 3 = 2 (500 - 300 = 200)

The thousands: 6 - 3 = 3 (6,000 - 3,000 = 3,000)

Our answer is 3,218

Now why don't you have a go at answering some questions?

Remember, we can do the inverse (opposite) operation to check answers!

Come back and look at the examples if you get stuck - simply click on the red help button on the screen at any point.