What is 4 + 4?
How did you figure it out?
- I know 4 + 4 = 8 because it's doubles
- I counted: 4, 5, 6, 7, 8
- I thought of 4 groups of 2 = 8
Doubles: Adding the same number twice (e.g., 3+3, 5+5, 8+8)
"I noticed that when we add doubles, the answer is always even. Why do you think that is?"
"When I see 4 + 4, I think 'four and four make eight.' I know this because doubles are like having two equal groups. Four in one group and four in another group makes eight altogether."
"I used my fingers to show 4 on each hand, and when I put them together I had 8 fingers!"
• Doubles facts are foundational for other addition strategies
• All doubles results are even numbers
• Knowing doubles helps with near doubles
What is 5 + 6?
How is this different from 5 + 5?
- 6 is one more than 5
- So 5 + 6 is one more than 5 + 5
- 5 + 5 = 10, so 5 + 6 = 11
Near Doubles: Adding consecutive numbers (e.g., 4+5, 7+8, 9+10)
"How can knowing 5 + 5 help you solve 5 + 6? What's the connection?"
"I know that 5 + 5 = 10, and 6 is one more than 5, so 5 + 6 must be one more than 10, which is 11. The numbers are 'near' each other, so I call it a near double!"
"I thought about 5 + 5 = 10, and then I added one more finger to make it 11!"
• Near doubles are addition problems with consecutive numbers
• Use known doubles facts to solve near doubles efficiently
• The result is always odd when adding consecutive numbers
0+0=0, 1+1=2, 2+2=4, 3+3=6, 4+4=8
What do you notice?
- All answers are even
- Answers increase by 2
- Doubles are multiples of 2
Patterns: Repeated sequences that help us predict and understand mathematical relationships
"If 7 + 7 = 14, what do you think 8 + 8 might be? How can you use the pattern?"
"I notice that each time I double the next number, the answer goes up by 2. So if 7 + 7 = 14, then 8 + 8 should be 16 because 14 + 2 = 16. The pattern continues!"
1+1=2
2+2=4
Increase by 2
Multiply by 2
4+4=8
5+5=10
"I see that every time we double the next number, we add 2 more to the answer!"
• Patterns help us make predictions about unknown facts
• Recognizing patterns strengthens mathematical reasoning
• Patterns connect different mathematical concepts
Number Talk: A structured conversation about solving math problems mentally, focusing on sharing and discussing different strategies.
Doubles: Addition facts where both addends are identical (e.g., 3+3, 8+8).
Near Doubles: Addition facts where addends are consecutive numbers (e.g., 4+5, 7+8).
- Pose the problem: Present a problem for mental calculation
- Think time: Allow students to solve mentally
- Share strategies: Students explain their thinking
- Discuss connections: Compare and connect different approaches
• Value all strategies and focus on the process, not just the answer
• Encourage students to listen to and build upon each other's ideas
• Make connections between different approaches explicit
• Create a safe space for risk-taking and learning from mistakes
Compare: 6 + 6 vs 6 + 7 vs 6 + 8
How are they related?
- 6 + 6 = 12 (doubles)
- 6 + 7 = 13 (near doubles)
- 6 + 8 = 14 (one more than near doubles)
Comparative Analysis: Examining relationships between similar problems to deepen understanding
"Look at 6 + 6, 6 + 7, and 6 + 8. What patterns do you see? How does knowing 6 + 6 help with the others?"
"I know 6 + 6 = 12. For 6 + 7, I just add one more to get 13. For 6 + 8, I add two more to get 14. Each time I add one more to the second number, the answer goes up by one!"
6 + 6 = 12
6 + 7 = 13
6 + 8 = 14
"I started with 6 + 6 = 12, then just counted up: 13, 14 for the next ones!"
• Starting with a known fact makes other problems easier
• Small changes in numbers create predictable changes in results
• Patterns help us solve problems we haven't seen before
Sarah has 8 stickers. Her friend gives her 9 more. How many does she have?
- This is 8 + 9
- 8 + 8 = 16, so 8 + 9 = 17
- It's a near doubles problem
Problem-Solving Talk: Using number talks to solve real-world mathematical problems
"How can we use our knowledge of doubles to solve story problems with near doubles?"
"I see this is 8 + 9. I know 8 + 8 = 16, and 9 is one more than 8, so 8 + 9 must be one more than 16, which is 17. Sarah has 17 stickers!"
"I knew 8 + 8 = 16, so 8 + 9 was just one more, which is 17!"
• Mathematical strategies apply to real-world problems
• Number talks help make connections between abstract and concrete
• Understanding patterns helps solve unfamiliar problems
Doubles: Addition facts where both addends are identical numbers (e.g., 2+2, 5+5, 9+9). These are foundational facts that help with other addition strategies.
Near Doubles: Addition facts where addends are consecutive numbers (differ by 1) such as 3+4, 6+7, 8+9. These can be solved efficiently using doubles facts.
Number Talk: A structured discussion format where students solve math problems mentally and share their thinking processes with peers.
- Pattern Recognition: Identifying doubles and near doubles in addition problems
- Strategy Development: Building efficient mental math approaches using known facts
- Communication: Explaining mathematical thinking clearly to others
- Connection Making: Linking different strategies and seeing mathematical relationships
1+1=2
2+2=4
3+3=6
4+4=8
5+5=10
7+7=14
8+8=16
9+9=18
10+10=20
1+2=3
2+3=5
3+4=7
4+5=9
5+6=11
• Doubles principle: n + n = 2n (always results in an even number)
• Near doubles principle: n + (n+1) = (n+n) + 1 (results in an odd number)
• Commutative property: Order of addends doesn't affect the sum
• Strategic thinking: Use known facts to solve unknown problems
- Allow adequate wait time for mental processing
- Record student thinking to make it visible
- Ask probing questions to deepen understanding
- Connect different strategies to show flexibility
- Celebrate multiple approaches to the same problem