## Adding Sets Of Double Digit Numbers

#### Aligned To Common Core Standard:

**Grade 2 Base Ten** - 2.NBT.6

These worksheets focus on adding set of four integers. This can be very helpful for a progression towards multiplication mastery. While this may seem like a simple skill for advanced students, other students will often get lost simply because they are not organized or perform their calculations in a sloppy way. I find that students when you coach students on how to set up their solution and provide them with a clear format that they will become successful at a much quicker rate. While being coordinated with your flow does not guarantee success, it does work out much quicker. I often begin by teaching students to focus on a pair of addends one at a time. Once they solve the first pair, take that sum, and add it to the next addend. Then finish it off by doing the same to the remaining addend. This is a piece-by-piece approach which is the first step. Once they have success with that, they have the concept in hand. At that point I would begin having them group all the addends into vertical columns.

### Adding Sets Of Integers Printable Worksheets And Lessons

- Step-by-step Lesson- Work on adding various sets of two-digit numbers. We start at pairs and move to 4 in a set.
- Guided Lesson - Two digit horizontal sums, sets of 3 two-digit numbers in vertical addition, count rows and add numbers.
- Guided Lesson Explanation - I walk you through how to approach all these problems.
- Practice Worksheet - Mixed sets of two-digit numbers in a vertical format.
- Matching Worksheet - Match the horizontal two-digit equations to their sum.

#### Homework Sheets

We start with minimum carrying and then we move to all carrying.

- Homework 1- The first one is completed for you. Follow that formula for solvingf the remaining problems.
- Homework 2 - There will be a great deal of regrouping on this page.
- Homework 3- A completely open sheet.

#### Practice Worksheets

It is tough for students at this level to organize these problems.

- Practice 1 - We included more whitespace for students to work with here.
- Practice 2 - Why would you not want to realign the addends before you dive in. You can do this by crossing one or more of them out and just restate it on top of all of them.
- Practice 3 - We use a few moe zeroes and ones here then before.

#### Math Skill Quizzes

You might find these to be a bit more fair, skill wise, than the practice sheets.

- Quiz 1 - These problems are lined up well for you to work your magic.
- Quiz 2 - We included more top or front heavy values here.
- Quiz 3 - It may help to rewrite some of these as you go through the exercise.

### How to Setup the Addition of Four Two-Digit Numbers

Adding two double digit numbers together is easy, but sometimes pupils in grade 1 and 2 face difficulty adding multiple double-digit numbers. Here is a step-by-step guide on how you can add 4 double-digit numbers easily. Let's say you have a problem in which you have to add the numbers 23, 42, 36, and 55. To make things easier, we'll put all the numbers in a vertical fashion.

23

+ 42

+ 36

__+ 55__

One way to solve this is to use a method called the break apart method in which we will break all these numbers into their expanded forms such as:

20 + 3, 40 + 2, 30 + 6, +50 + 5

Now, as you can see, these numbers have been expanded into simpler forms, making it easier for them to be added. Now we will add them

20 + 3, 40 + 2, 30 + 6, +50 + 5 or 140 + 16 =

Now, you add 140 + 16, which makes up 156.

Break apart method is one of the simplest addition methods you can use to make the addition of multiple numbers simpler and easier.

**Something to Keep in Mind for Teacher**

When you are working on this skill with students it is a perfect time to introduce them to the commutative property of addition. This property tells us that the order in which place addends does not matter one bit. The sum will not change based on the position of addend within an equation. I share this with students and ask them to consider reordering addends if they see a pattern or something that would make solving the problem easier for them. We will explore this in the problem found below:

**Problem:** Find the sum of 25, 36, 65, 54.

**Solution:** We would normally set this up in the order that it was presented to us in such as: 25 + 36 + 65 + 54 = ___

Keeping the commutative property of addition in our mind we see an order of the addends that would make it much easier to work with. Look at the ones place of all the numbers. There are integers that would quickly make nice round numbers by making 10.

This problem would be better restated as: 25 + 65 + 36 + 54

So, we pair up the values that end in 5s because when we add them, we get a 10. We also pair up the integers that end in 6 and 4 because they do the same. We can easily add up those pairs and reduce the calculation from: 25 + 65 + 36 + 54 = 90 + 90 = 180

This is a great habit to get students into. Practice and lots of repetition will get them to make this part of their process.