Addition Of Two Three Digit Numbers Quiz for students
Learn to add two 3 digit numbers
Addition is an important mathematical operation that is used to find the sum of two or more numbers. In this lesson, we’ll be learning how to add two three-digit numbers together.
A three-digit number is a number that has three digits, such as 123, 456, and 789. To add two three-digit numbers together, we use a process called column addition.
Column addition is a method of adding numbers by aligning them in columns and adding them up one column at a time. Let’s look at an example to see how it works.
Example: Let’s say we want to add the numbers 123 and 456.
We’ll start by aligning the numbers in columns, with the ones digits, tens digits, and hundreds digits lined up.
123
+ 456
-----
The first column is the ones digits column. We’ll start by adding the ones digits of the two numbers, which are 3 and 6. 3 + 6 = 9, so we write the 9 in the ones digit of the answer and carry over the 1.
123
+ 456
-----
9
Next, we move on to the tens digits column. We add the tens digits of the two numbers, which are 2 and 5, and add the 1 that we carried over from the ones digits. 2 + 5 + 1 = 8, so we write the 8 in the tens digit of the answer and carry over the 1.
123
+ 456
-----
89
Finally, we move on to the hundreds digits column. We add the hundreds digits of the two numbers, which are 1 and 4, and add the 1 that we carried over from the tens digits. 1 + 4 + 1 = 6, so we write the 6 in the hundreds digit of the answer.
123
+ 456
-----
579
And there you have it! The sum of 123 and 456 is 579.
Another example:
Example: Let’s say we want to add the numbers 345 and 876
345
+ 876
-----
We start adding the ones digit, in this case 5+6=11 so we write 1 in the ones digit of the answer and carry over the 1.
345
+ 876
-----
1
We move on to the tens digits, 4+7+1=12 so we write 2 in the tens digit of the answer and carry over the 1
345
+ 876
-----
21
Finally we move on to the hundreds digits and add 3+8+1=12 so we write 12 as our answer
345
+ 876
-----
1221
As you can see the process is the same as the previous example, with carrying over digits if the sum of any column is greater than 9.
It’s important to practice addition of three digit numbers to become more proficient in math. Also if you are struggling with carrying over or if you are making mistakes it can be useful to go back and practice single digit addition and the concept of carrying over.