Adding by 3
It is easy to add! You can find the total amount when you add. When you join objects together, you can find how many there are in all, or altogether.
You can add anything! Try adding pencils, candy, or toys. How many objects are there in all?
Sometimes we have a group of objects and we want to add exactly 3 more objects to that group. Like this:
There are 4 hearts in the first group and 3 more hearts in the second group.
We can ADD them! This is done by joining the two amounts together.
This will give us the total number of hearts.
When we ADD 4 plus 3, we have 7 in all.
We say: FOUR plus THREE equals SEVEN.
We write it like this: 4 + 3 = 7.
Here is another example.
In this problem, we are joining together 2 groups of apples.
We are ADDING them together.
This will give us the total number of crayons.
When we ADD 1 plus 3, we have 4 in all.
We say: ONE plus THREE equals FOUR.
We write it like this: 1 + 3 = 4.
These numbers are known as ADDENDS.
Addends are the amounts that will be joined together.
This problem reads as 7 + 3 = 10.
When the ADDEND 7 is joined with the ADDEND 3, we get a SUM of 10.
SUM is used to describe the total amount.
When we add THREE MORE to a group of objects, we can remember that the SUM will be the number that comes three after that number when we are counting.
6 + 3 =
For example, 6 + 3 = 9. We also know that when we count, the number that comes three after 6 is the number 9. We can say: SIX… SEVEN, EIGHT, NINE. We have counted up THREE to get to the number NINE. This can help us to add quickly and correctly when adding 3 to a group.
7 + 3 =
Let’s try another example. What is 7 + 3? We can add or count three more from the number 7. We know that the number that comes after 7 is the number 8 and that the number that comes after 8 is the number 9. Finally, we know that 10 comes after 9. SEVEN… EIGHT, NINE, TEN. Therefore, 7 + 3 = 10.
3 + 10 =
Here is another example. This time our 3 comes first and our larger group comes second. We can still solve in the same way. What is 3 + 10? We can add or count on three more from the number 10. This time, draw a picture to solve. Make a group of three objects and another group of 10 objects. Then count them altogether to find the total. When we solve, we will find out that 3 + 10 = 13.
Look at the example above. Two groups are being joined together to find the total.
3 yellow pencils plus 2 red pencils will tell us how many pencils there are in all.
We can count the pictures and join the groups together to find the total.
3 yellow pencils + 2 red pencils = 5 pencils in all.
There are 5 pencils in all.
There are many different words that are used to describe addition. For example, we can COMBINE two amounts together to find the SUM. Here are several other examples:
Knowing these keywords will help you understand that in order to solve the problem, you must add. You might see these keywords in math story problems.
We can also add 3 in story problems.
In the problem, the children join together on the playground. The key words are JOIN IN as well as ALTOGETHER. This helps tell us that we need to ADD.
FIVE boys are joined with THREE girls on the playground and this will give us the correct SUM.
We can count up three from five to help us find the answer.
5 + 3 = 8 altogether
There are many additional strategies you can use to help you add correctly. We will continue to learn about these in other lessons.
Practice Question 1
Let’s practice! Write the addition sentence and solve the problem below.
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Practice Question 2
Let’s try another! Write the addition sentence and solve the problem below.
Practice Question 3
Take a look at the math sentence below. Draw a picture to match it. Then solve.
10 + 3 =
Practice Question 4
Look at the groups below.
How many pieces of fruit are there in all?
Write an addition sentence and solve.
Practice Question 5
Look at the buildings below.
How many buildings are there in all?
Write an addition sentence and solve.