Child Safe
Parent Monitoring
Adding Doubles Minus 1
Overview
The adding doubles strategy is very helpful and in the previous lesson, we reviewed on Adding Doubles Plus 1.
In this lesson, we will apply the same exact strategies and learn how to use the adding doubles minus 1 to help us quickly solve certain addition problems.
Incase you forgot what adding doubles is, let’s review!
When you add two of the SAME number, you are adding with DOUBLES FACTS.
1 + 1 and 2 + 2 are both doubles facts.
Look at the example below:
3 + 3 = 6 is a doubles fact.
Take a look at this special addition problem below, where we can use our knowledge of doubles fact and simply minus 1 to quickly get the answer.
3 + 2 =
We know that 3 + 3 = 6, so 3 + 2 must have a sum that is one less.
Therefore,
3 + 2 =5
Doubles facts are easy to remember. Look at the pattern below.
Let’s try a few doubles minus 1 facts! Use the pictures to help you solve.
4 + 3 =
4 + 4 = 8, so 4 + 3 = 7
6 + 5 =
6 + 6 = 12, so 6 + 5 = 11
5 + 4 =
5 + 5 = 10, so 5 + 4 = 9
2 + 1 =
2 + 2 = 4, so 2 + 1 = 3
Remembering the doubles facts can help you with other math problems too!
K8 New
Free
save 68%
Our monthly subscription plan offers unlimited access to all of our premium video lectures, practice questions, and quizzes. If you want on-demand access to our educational resources, this plan is perfect for you.
Our data shows that 96% of those who get our award-winning K-8 Math & Reading program stick with it.
These are parents just like you with kids just like yours. They start watching and… keep going.
Practice Question 1
Use the adding doubles minus 1 strategy to solve questions 1 through 5.
8 + 7 =
Practice Question 2
5 + 4 =
Practice Question 3
3 + 2 =
Practice Question 4
7 + 6 =
Practice Question 5
5 + 4 =
Doubles facts can help you to find the sum of many different addition problems!
Create your free account to see answers!
Welcome
You have successfully logged in.
Click to show more