Introduction
When we are asked to add numbers such as 15 + 5, we can sometimes work out the answer in our heads.
However, when we are given questions with bigger numbers, we might need to use a written method.
In this activity, we’ll look at the columnar method to add numbers.
Let’s have a look at how we can use the method to add 42 + 44
First, we write the numbers in columns under the correct unit (T = tens, O = ones ).
T O
4 2
4 4
Starting at the right-hand column (ones) we add each column and write the answers underneath.
T O
4 2
4 4
9 6
42 + 44 = 86
Here’s another example:
T O
7 2
2 5
9 7
72 + 25 = 97
With this method, it is vital that we start with the ones column! This is because when the digits in a column add up to ten or more, we have to exchange, sometimes known as ‘borrowing’ – we’ll look at this in another activity!
Now, why don’t you have a go at answering some questions using this method?
