LESSON: Operations with Whole Numbers
READ: Adding Whole Numbers
Adding Whole Numbers
Let’s start with something that you have been doing for a long time. You have been adding whole numbers almost as long as you have been in school. Here is a problem that will look familiar.
Example
In this problem, we are adding four and five. We have four whole things plus five whole things and we get an answer of nine.
The numbers that we are adding are called addends. The answer to an addition problem is the sum.
This first problem was written horizontally or across. In the past, you may have seen them written vertically or up and down. You will need to be able to write your problems vertically on your own. How do we do this? We can add whole numbers by writing them vertically according to place value.
Place value is when you write each number according to the value that it has.
| Millions | Hundred Thousands | Ten Thousands | Thousands | Hundreds | Tens | Ones |
| 1 | 4 | 5 | 3 | 2 | 2 | 1 |
This number is 1,453,221. If we used words, we would say it is one million, four hundred and fifty-three thousand, two hundred and twenty-one.
What does this have to do with adding whole numbers?
When you add whole numbers, you write them vertically according to place value.
Think about the example we had earlier.
If we wrote that vertically, we would line up the numbers. They are both ones.
What happens when you have more digits?
Example
When you have more digits, you can write the problem vertically by lining up each digit according to place value.
Now we can add the columns.