These worksheets focus on summing three integers that all contain three digits.

In this section of our site, we will work finding the sum of 3 addends. This is a very common work-related form of math. Many jobs require this skill as a basic requirement, even if it is a very minimal task. We can look at this topic as a required for a successful life skill. You will find a whole lesson set and quiz for this section. You just need to scroll down to find those bad boys. Some people say that they are not good at math, but in most cases that just isn't true. The lesson really will help you go from zero to sixty pretty quickly. It helps if you are good with basic math facts. In many cases, just restating the addition problem and putting it in a format that works better for you is more than enough to help.

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Print Adding 3 Triple Digit Numbers Worksheets

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Introduction Lesson

We walk you through the process of long hand addition and follow it up with two practice problems. Everything is fully explained in this lesson.

Three Sums Worksheet

Worksheet 1

We made it so that in some there would be minimal carrying over of places and then others are all about carrying. You can use the triple column method here.

Three Sums Worksheet 2

Worksheet 2

We got very bold with this worksheet. On number 1 and 10 we have a thousands and ten-thousands place.

Skill Review Worksheet


This is a five-step process walk through for you. We cover it top to bottom. We show you how we rename columns and perfect the way in which we carry values across columns.

Followup Worksheet

Followup Sheet

This worksheet builds up what was shown on the review sheet. You are on your own here.

Skill Quiz


A ten-question quiz on adding 3 three-digit sums together. Complete with a scoring key found on the bottom of the page.

Do Now Worksheet

Do Now!

This is a nice reminder of how to do this. If any students are absent, have them complete this first to see where they are at with this skill.

How to Add 3 Triple-Digit Numbers

The addition of 3-digit numbers is not as difficult as it may seem. Most students learn to add 3-digit numbers after a few tries. While this may be true, the addition of multiple numbers with more than a single-digit can frustrate kids. If you are a school teacher, you may be able to get accurate answers for two-number multiple-digit addition problems from your students. However, they may not be able to add three triple-digit numbers easily.

If you face trouble teaching them how to add three triple-digit numbers, we can help you try the simplest methods to improve their learning. Kids often encounter problems with complex arithmetic equations. They may fail to deliver regardless of their knowledge of different mathematical functions.

You can try the following simple ways to ensure they do not miss out on learning the addition of different number types.

Adding Three Triple-Digit Numbers

The Two-Plus-One Method

One of the most effective ways to teach kids the addition of three triple-digit numbers is by using (what we call) the two-plus-one method. This method is exactly how it sounds.

In this addition method, you can take two of the three numbers and add them first. For example, if you have three triple-digit numbers, 245, 300, and 421, you can add the first two numbers using the column addition method.

- Start with adding the digits on one's place, 5 + 0 = 5

- Add the digits present on the ten's place, 4 + 0 = 4

- Now, add the digits on the hundred's place, 2 + 3 = 5

The sum of the numbers 245 and 300 comes out to be 545.

Now, you can add the third number to the sum of the first two numbers. You can apply the column addition rule again.

- Add the two digits present in one's place, 1 + 5 = 6

- Please move to the digits on the ten's place and add them; 2 + 4 = 6

- In the final step, add the two digits in the hundred's place, 4 + 5 = 9

The total of 545 + 421 = 966.

Using this method, you can break the addition of three triple-digit numbers into two parts and apply the column addition method to obtain the total.

The Triple Column Addition Method

If you trust your students with a more challenging way of adding three triple-digit numbers, you can use the triple column addition method.

To apply this rule, you can use the column addition technique for all three numbers simultaneously. For example, if you have three numbers, 281, 462, and 511, you can place them in a column format and apply vertical addition on each digit's place.

To add three numbers simultaneously, consider the following steps:

- Please start with the digits on one's place and add them, 1 + 2 + 1 =4

- Move to the ten's place and add the three digits vertically, 8 + 6 + 1 = 15

- Place the value at one's place in the result's row and carry one to the next digit

- Now, add the three digits in the hundred's place and the carry-forward value, 1 +2 + 4 + 5 = 12.

- Write the value on one's place in the hundred's place of the result's row and the value on the ten's place before it to get the total.

The sum of 281, 462, and 511 comes out to be 1254.

Summing Up

The methods mentioned above can help you teach your students to learn the addition of three triple-digit numbers. For kids who face problems learning sums, you can opt for the first method. If you want to find other examples, you can search online for some of the many helpful resources for teachers and students.