📖Definition
We do simple addition and subtraction all the time in our heads. When the numbers become more complicated we can use the Column methods.
Column Addition is a written method of adding numbers together for those times when a calculator isn't allowed or available. Similarly, Column Subtraction can be used when taking numbers away from each other.
💡Tips/hints
The clue is in the title - put the numbers in columns!
Be careful to put your workings (the carried digits and the borrowed ones) in the correct columns.
✏️Example
Maisie empties out her three piggy banks. They contain £5.24, £0.71 and £8.33. How much does she have in total?
Diagram
✅Solution
First write the sum in columns, lining up the decimal points.
Add the numbers in the right hand column.
4 + 1 + 3 = 8. Write 8 in the answer line.
Now add the column to the left of this.
2 + 7 + 3 = 12. Put the 2 in the answer line and put the 1 below the answer line in the next column.
Finally, add the column to the left of the decimal point including the 1 below the answer line.
5 + 0 + 8 + 1 = 14. Write that in the answer line for the solution.
✏️Example
Jonah has been collecting football stickers. He has a total of 756 but decides to give 74 to his brother. How many will he have left?
We need to subtract 74 from 756.
First write the sum in columns.
Diagram
✅Solution
Subtract the units (right hand column).
6 - 4 = 2. Write 2 in the answer line below.
Next subtract the Tens column
But 5 - 7 gives a negative result so, we need to borrow from next column. We take a 1, so the 7 becomes a 6, and we give the 1 to the 5 making it 15.
The subtraction in the tens column is now 15 - 7 = 8. Write that in the answer line.
Finally, the hundreds subtraction is 6 - 0 = 6 which we put in the answer line.
So, he'll have 682 stickers left.