Adding whole numbers means combining numbers to form a total. Each number being added is called an addend, and the total (the answer to the addition problem) is called the sum.
Adding numbers with 1 digit is straightforward. You can often do it mentally or use your fingers. Remember, adding zero to a number never changes the number.
Quick Quiz:
Take a close look at the following addition problems. One of them is wrong. Can you tell which one?
Answer: The first one is incorrect. 4 + 6 = 10, not 11.
When adding two-digit numbers, add the ones first, then add the tens.
Example 1: 36 + 17
Using expanded notation:
Therefore, 36 + 17 = 53
Example 2: 58 + 46
Using expanded notation:
Therefore, 58 + 46 = 104
We can accomplish the same by arranging the numbers in vertical columns:
| 1 | ||
| 5 | 8 | |
| + | 4 | 6 |
| 1 | 0 | 4 |
In vertical addition:
The 1 that we carry over has a place value of 10. We don't need to write 10 because putting a 1 in the tens place means there is 1 ten.
| 1 | 1 | ||
| 3 | 6 | 7 | |
| + | 2 | 8 | 5 |
| 6 | 5 | 2 |
Steps for adding 367 + 285:
| 1 | 2 | ||
| 2 | 5 | 4 | |
| 3 | 7 | 8 | |
| + | 1 | 4 | 9 |
| 7 | 8 | 1 |
Steps for adding 254 + 378 + 149:
In all examples, we start from the rightmost column (ones) and work our way left, carrying over when necessary. This method works for adding any number of whole numbers with any number of digits.