Doubles facts are addition facts where the same number is added to itself, such as 4 + 4 or 6 + 6. They are helpful because they appear often in counting, games, money, and classroom math. Early learners can picture doubles as two equal groups, like two socks, two shoes, or two hands with the same number of fingers showing.
When both sides match, the total is easier to remember.
Key Facts
- A doubles fact has the form n + n = total.
- The total of a doubles fact is always an even number.
- 4 + 4 = 8.
- 6 + 6 = 12.
- A double is the same as counting two equal groups.
- Knowing doubles helps with near doubles, such as 5 + 6 = 5 + 5 + 1.
Vocabulary
- Double
- A double is the sum made by adding a number to itself.
- Equal groups
- Equal groups are groups that have the same number of objects.
- Sum
- The sum is the answer to an addition problem.
- Addend
- An addend is a number being added in an addition sentence.
- Even number
- An even number can be split into two equal whole number groups.
Common Mistakes to Avoid
- Adding two different numbers and calling it a double is wrong because a double must use the same number twice, like 7 + 7.
- Counting only one group is wrong because a doubles fact combines both equal groups to find the total.
- Forgetting that doubles totals are even is wrong because two matching whole number groups always make an even total.
- Mixing up the sum with an addend is wrong because in 6 + 6 = 12, 6 is an addend and 12 is the sum.
Practice Questions
- 1 Solve: 4 + 4 = ?
- 2 Solve: 6 + 6 = ?
- 3 A pair of shoes has 2 shoes, and another matching pair also has 2 shoes. Explain why 2 + 2 is a doubles fact.