Doubles Near Doubles

Key Concepts

• Doubles Fact
• Near Doubles Fact

Introduction  

Doubles

To get a double of a number, we add the same number to itself.  

For example, double of 3 is 3 + 3 = 6.  

Example 1:  

Jenny has 4 marbles and she has bought 4 more new marbles. How many marbles does Jenny have? 

Solution: 

The double of 4 is 8.  

Doubles fact 

Example 2: 

Find 5 + 5. 

Solution: 

Let’s take some cubes to solve this. 

Doubles fact: 5 + 5 = 10 

Example 3: 

Find 9 + 9. 

Solution: 

Let’s take some cubes to solve this. 

Doubles fact: 9 + 9 = 18 

Near doubles fact 

When adding numbers that follow each other, use the knowledge of doubles to help add the numbers. 

3 + 4 is same as 3 + 3 + 1 = 7 

Example 4: 

Find 4 + 5. 

Solution: 

Double fact: 4 + 4 = 8 

4 + 5 is one more than 4 + 4. 

Near Doubles fact: 4 + 5 = 9 

Example 5: 

Find 10 + 8. 

Solution: 

Double fact: 8 + 8 = 16 

10 + 8 is two more than 8 + 8. 

Near Doubles fact: 10+ 8 = 18 

Exercise

1. Complete the doubles fact. Use cubes if needed.
   8 + 8 = ______
2. Choose all the pictures that represent a double.

3. Complete the doubles fact. Use cubes if needed.
   2 + 2 = ______
4. Complete the doubles fact. Use cubes if needed.
   5 + 5 = ______
5. Complete the doubles fact. Use cubes if needed.
   10 +10 = ______
6. Use the doubles facts and solve the near doubles. Use cubes if
   needed.
   3 + 2 = ______
7. Use the doubles facts and solve the near doubles. Use cubes if
   needed.
   5 + 6 = ______
8. Use the doubles facts and solve the near doubles. Use cubes if
   needed.
   

Concept Map

What have we learned

• Use Doubles fact and add two numbers that are the same.
• Use Near Doubles fact and add two numbers that follow each other.