1. Strong Start Math Project November 10, 2016

2. Tonight’s Agenda Developmental Levels of Thinking for Subtraction
Subtraction Strategies
Wrap up for Fall
Mathematical Curiosity with Gabriella

3. Learning Intentions & Success Criteria
We are learning to…
deepen our understanding of levels of thinking for addition and subtraction basic facts.
We will be successful when we can…
recognize levels of thinking in children’s work.
describe and record thinking strategies.
scaffold subtraction strategies from missing part activities.

4. Meaning of Subtraction
Read each problem one by one:
name the missing part.
name the story problem structure.
Pick a context for each problem:
Subtraction as take away
Subtraction as comparison
Subtraction as distance

5. Levels of Reasoning for Subtraction
Level 1: Direct Modeling by Taking Away (Count, Count, Count)
Level 2: Counting On by Ones (Think Addition)
Counting Back by Ones
(Think Subtraction)
Level 3: Convert to an Easier Equivalent Problem (Get to 10: Think Subtraction)
(Get to 10: Think Addition)
(Use Doubles: Think Addition)
Use Take from RU to model through levels ( Bridget). What are the different ways kids might solve this problem?

6. Thinking about subtraction strategies
Bridget has 13 mini candy bars. She ate 7 of them during parent teacher conferences. How many mini candy bars does Bridget have left?
What are the different ways children of different ages might enter into this problem?

7. Listening to Children’s Thinking
As you listen to the students in the video, note how the thinking changes from Tyler to Janet to Artemius.

8. Level 1: Direct Modeling by Counting All or Taking Away
Bridget has 13 mini candy bars. She ate 7 of them during parent teacher conferences. How many mini candy bars does Bridget have left?
Represent the total.
Take the “known addend” away.
Count the resulting groups of objects to find the unknown addend.
Works for “Take From Result Unknown”
Take the Level 1 Strategy from the Bridget Problem and chart it here while participants record on

9. Level 2: Counting Back & Counting On
= __ Count back Start at 13. Count back 12, 11, 10, 9, 8, 7, Count on Start at 7. Count up 8, 9, 10, 11, 12,
Keeping track on fingers.
Bridget has 13 mini candy bars.
She ate 7 of them during
parent teacher conferences. How many mini candy bars
does Bridget have left?

10. Level 2: Count On by Ones Count Back by Ones
Count On by Ones For 10 – 8, find the number that makes 10 when added to 8. Think: 8 + ☐= 10 Count on: 8, 9, My answer is 2.
Count Back by Ones For 11 – 2, count back 2. Count back: 11, 10, 9 My answer is 9.
Count back by ones
When you are removing 1, 2, or 3
Count on by ones
When the difference between the total and known addend is 1, 2, or 3

11. Subtraction Strategies: Level 3. Convert to an Easier Problem

12. Grade 1: 1.OA.6
Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., = = = 14); decomposing a number leading to a ten (e.g., = = = 9); using the relationship between addition and subtraction (e.g., knowing that = 12, one knows = 4); and creating equivalent but easier [equivalent problems].
Optional slide….. Point being, not all standards are created equal and this one standard might require attention all school year in first grade and be a major component of your instruction and assessment.

13. Level 3 Convert to an Easier Problem to Subtract
Level 3 Subtraction Strategies
Think Subtraction: Get to 10
(1.OA.6 Decompose a number leading to a ten)
Think Addition: Get to 10
Think Addition: Use Doubles

14. Think Subtraction: Get to 10 1. OA
Think Subtraction: Get to 10 1.OA.6 Decompose a number leading to a ten

15. Level 3. Convert to an Easier Problem Think Subtraction: Get to 10
I bought 13 balloons to decorate for my party.
Sadly, 7 of those balloons popped. How many balloons
do I have left?
What number would we “decompose leading to a ten?” Solve and state the reasoning used to your partner. Decompose 7 into 3 and balloons remove 3 balloons is 10 balloons. 10 balloons remove 4 balloons is 6 balloons. I have 6 balloons left. What number sentence(s) would match this thinking?

16. Level 3. Convert to an Easier Problem Think Subtraction: Get to 10
I bought 13 balloons to decorate for my party.
Sadly, 7 of those balloons popped. How many balloons
do I have left?
Option 1:
13 – 7 = 12 – 3 – 4 = 6
Option 2:
13 – 7 = ☐ – 3 =10
10 – 4 = 6
3 4

17. Level 3. Convert to an Easier Problem Think Subtraction: Get to 10
I bought 13 balloons to decorate for my party. Sadly, 7 of those balloons popped. How many balloons do I have left?
6 remain
6 remain
Remove 4 -4 -3
Remove 3
13 – 3 = 10
10 – 4 = 6

18. Level 3. Convert to an Easier Problem Think Subtraction: Get to 10
13 – 7 = ☐
3 4
13 – 7 = 13 – 3 – 4 = 10 – 4 = 6
13 – 3 = 10
10 – 4 = 6

19. Think Addition: Get to 10 Think Addition: Use Doubles

20. Level 3. Convert to an Easier Problem Think Addition to Subtract
Think Addition: Get to 10
Think Addition: Use Doubles
Amy is preparing to do pumpkin math with her kindergartners. She has 7 pumpkins. How many more pumpkins does she need to have 13 pumpkins?

21. Level 3. Convert to an Easier Problem Think Addition: Get to 10
Solve and state the reasoning used with your partner.
Amy is preparing to do pumpkin math with her kindergartners. She has 7 pumpkins. How many more pumpkins does she need to have 13 pumpkins?

22. Level 3. Convert to an Easier Problem Get to 10: Think Addition
7 + ☐ = 13 +3 +3 . +3 +3
Reasoning may sound like :
7 + 3 is 10. Three more is 13.
3 and 3 is 6.
7 + 6 = 13 The answer is 6.

23. Level 3. Convert to an Easier Problem Think Addition: Get to 10
7 + ☐ = 13 6
= 10
= = 6

24. Level 3. Convert to an Easier Problem Think Addition: Use Doubles
Solve and state the reasoning used with your partner.
Amy is preparing to do pumpkin math with her kindergartners. She has 7 pumpkins. How many more pumpkins does she need to have 13 pumpkins?

25. Level 3. Convert to an Easier Problem Think Addition: Use Doubles
7 + ☐ = 13 +7 . +7
Reasoning may sound like :
7 + 7 is 14. One less is 13.
7 + 6 = 13
The answer is 6.

26. Level 3. Convert to an Easier Problem Think Addition: Use Doubles
7 + ☐ = 13 +7
= 14
= 13
= 6
The answer is 6.

27. Time to Practice Pick one strategy and use it to solve each problem:
14 – 9 = 16 – 7 = 15 – 8 =
Pick one strategy and use it to solve each problem:
Think Subtraction: Get to 10
Think Addition: Get to 10
Think Addition: Use Doubles

28. Learning Intentions & Success Criteria
We are learning to…
deepen our understanding of levels of thinking for addition and subtraction basic facts.
We will be successful when we can…
recognize levels of thinking in children’s work.
describe and record thinking strategies.
scaffold subtraction strategies from missing part activities.

29. Fall wrap up

30. All Manner of Miscellaneous & PRESENTS!
Number Talks Book & Rekenrek Book
Rekenreks!! 
Electronic resources on the back page of homework sheet

31. Homework

32. King/Bay Williams Reading Instructional Guidelines: Three Phases to Fluency
Phase 1 Direct Modeling by Taking Away & Counting On
Phase 2 Using reasoning strategies
Phase 3 Mastery or efficient production of answers.

33. Mathematical Curiosity with Gabriela