Grade 2: Chapter 5 – 2-Digit Subtraction

Chapter Essential Question:How do you use place value to subtract 2-digit numbers with and without regrouping?

Before
(Grade One) / Chapter Five Standards
Grade Two / After
(Grade Three)
Represent and solve problems involving addition and subtraction.
(1.OA.1)
Use place value understanding and properties of operations to add and subtract.
(1.NBT.4) / Number & Operations in Base Ten 5:Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
  • I can break apart a 1-digit subtrahend to subtract it from a 2-digit number.
  • I can break apart a 2-digit subtrahend to subtract it from a 2-digit number.
  • I can model 2-digit subtraction with regrouping.
  • I can draw quick pictures and record 2-digit subtraction using the standard algorithm.
  • I can record 2-digit subtraction using the standard algorithm.
  • I can practice 2-digit subtraction with and without regrouping.
  • I can rewrite horizontal subtraction problems vertically.
  • I can use addition to find differences.
/ Represent and solve problems involving multiplication and division.
(3.OA.1)
Use place value understanding and properties of operations to perform multi-digit arithmetic.
(3.NBT.2)
Operations & Algebraic Thinking 1: Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.
  • I can solve problems involving 2-digit subtraction by using the strategy draw a diagram.
  • I can represent subtraction situations with number sentences using a symbol for the unknown number.
  • I can analyze word problems to determine what operations to use to solve multistep problems.

Number & Operations in Base Ten 9:Explain why addition and subtraction strategies work, using place value and the properties of operations.
  • I can model 2-digit subtraction with regrouping.

Each day the math block will begin with 15 minutes of Daily Math Review and Mental Math. The focus of DMR should be either prerequisite standard skills or previous chapter concepts that were not mastered. The focus of mental math should be based on the current Chapter’s skills and concepts. Adjust the amount of questions in DMR and MM to fit into the 15 minute time block.

Suggested Chapter Pacing

All lessons are paced for one day, unless otherwise indicated. Teachers may adjust to meet students’ needs.

Launching the Chapter / Pre-Assessment / Review Prerequisite Skills
Count on Me Subtraction! TE 313I
Regroup to 100! TE 313I / Show What You Know Assessment
Identify Tier 2 and Tier 3 Groups for Small Group Instruction.
Day Before Lesson 5.1 / Vocabulary Activity
Bingo TE 316A / Vocabulary Builder
TE 315 - Identify students who will need further vocabulary support for Chapter Five. / Preview Chapter Centers
Introduce chapter games, activities, and literature students will be using during center time. / School – Home Letter
Read together and send home.
I Can Statement / Essential Question / Implementation Notes / Centers by Lesson / Teacher Notes
Lesson 5.1
NBT.5 / I can break apart a 1-digit subtrahend to subtract it from a 2-digit number. / How does breaking apart a number make subtracting easier? / As well as breaking up the subtrahend, students could use a compensating strategy:
32 – 7 = (32 – 2) – 5; 32 – 7 = (32 – 10) + 3 / A: Ways to Go
L: Comic Books for Sale
G: Subtraction Action / Click here to enter text.
5.1 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
None / Animated Math Model:
None
Lesson 5.2
NBT.5 / I can break apart a 2-digit subtrahend to subtract it from a 2-digit number. / How does breaking apart a number make subtracting easier? / As well as breaking up the subtrahend, students could use a compensating strategy:
32 – 17 = (32 – 10) – 2 – 5; 32 – 17 = (32 – 20) + 3 / A: Ways to Go
L: Comic Books for Sale
G: Subtraction Action / Click here to enter text.
5.2 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
None / Animated Math Model:
None
Lesson 5.3
NBT.5
NBT.9 / I can model 2-digit subtraction with regrouping. / When do you regroup in subtraction? / Use Base Ten Block
There are other acceptable strategies other than trading a ten for 10 ones that can be used.
Students may continue to use strategies based in place value. Teachers need not feel obligated to move students to using a standard algorithm in second grade. / A: Sticker Subtraction
L: Comic Books for Sale
G: What is the Difference / Click here to enter text.
5.3 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
Country Countdown: Block Busters – Level Q / Animated Math Model:
Model 2-Digit Subtraction
Lesson 5.4
NBT.5 / I can draw quick pictures and record 2-digit subtraction using the standard algorithm. / How do you record 2-digit subtraction? / Use Base Ten Block
Same note as in 5.3 / A: Regrouping
L: Comic Books for Sale
G: What is the Difference / Click here to enter text.
5.4 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
Country Countdown: Block Busters – Level R / Animated Math Model:
Model + Record 2-Digit Subtraction
Lesson 5.5
NBT.5 / I can record 2-digit subtraction using the standard algorithm. / How do you record the steps when subtracting 2-digit numbers? / Use Base Ten Block
Same note as in 5.3 / A: Super Subtraction
L: Comic Books for Sale
G: What is the Difference / Click here to enter text.
5.5 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
Country Countdown: Block Busters – Level R
Numberopolis: Carnival Stories – Level M
Numberopolis: Carnival Stories – Level Q / Animated Math Model:
2-Digit Subtraction
Lesson 5.6
NBT.5 / I can practice 2-digit subtraction with and without regrouping. / How do you record the steps when subtracting 2-digit numbers? / Same note as in 5.3
Mid-Chapter Checkpoint Optional / A: Measuring Up
L: Comic Books for Sale
G: What is the Difference / Click here to enter text.
5.6 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
Numberopolis: Carnival Stories – Level R / Animated Math Model:
Practice 2-Digit Subtraction
I Can Statement / Essential Question / Implementation Notes / Centers by Lesson / Teacher Notes
Lesson 5.7
NBT.5 / I can rewrite horizontal subtraction problems vertically in the standard algorithm format. / What are two different ways to write subtraction problems? / Same note as in 5.3 / A: Measuring Up
L: Comic Books for Sale
G: What is the Difference / Click here to enter text.
5.7 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
Country Countdown: Block Busters – Level Q / Animated Math Model:
Rewrite 2-Digit Subtraction
Lesson 5.8
NBT.5 / I can use addition to find differences. / How can you use addition to solve subtractions problems? / This strategy will resonate with many students.
This can be shown on an open number line as well. / A: We’re in the Money
L: Party Plans
G: What is the Difference / Click here to enter text.
5.8 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
None / Animated Math Model:
None
Lesson 5.9
OA.1 / I can solve problems involving 2-digit subtraction by using the strategy draw a diagram. / How can drawing a diagram help when solving subtraction problems? / Students may use a different equation to represent the problems.
Students may use any strategy to solve the problems. / A: We’re in the Money
L: Party Plans
G: What is the Difference / Click here to enter text.
5.9 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
None / Animated Math Model:
None
Lesson 5.10
OA.1 / I can represent subtraction situations with number sentences using a symbol for the unknown number. / How do you write a number sentence to represent a problem? / Same as 5.9 / A: We’re in the Money
L: Party Plans
G: What is the Difference / Click here to enter text.
5.10 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
Country Countdown: Block Busters – Level Q / Animated Math Model:
None
Lesson 5.11
OA.1 / I can analyze word problems to determine what operations to use to solve multistep word problems. / How do you decide what steps to do to solve a problem? / Same as 5.9 / A: We’re in the Money
L: Party Plans
G: What is the Difference / Click here to enter text.
5.11 Technology / Interactive Whiteboard Lesson / Interactive Student Edition (Engage) / Math on the Spot / Mega Math:
None / Animated Math Model:
Problem Solving Skill: Solve Multistep Problems
Additional Resources for Chapter 5
Operations in Algebraic Thinking 5 / Number and Operations in Base Ten 1 / Number and Operations in Base Ten 9
Digit Switcher
Three Digit Shuffle
Pick Up Sticks
Thinking About Place Value
Different Ways to Make the Same Number / CGI – Addition and Subtraction Story Bank

‘

2.NBT.9: What does this standard mean the students will know and be able to do?
This standard calls for students to explain using concrete objects, pictures and words (oral or written) why addition or subtraction strategies work. The expectation is that students apply their knowledge of place value and the properties of operations in their explanation.
Students should have the opportunity to solve problems and then explain why their strategies work.
Students could also have experiences examining strategies and explaining why they work. Also include incorrect examples for students to examine. Operations embedded within meaningful context promote development of reasoning and justification.
Example A
One of your classmates solved the problem 56 - 34 = __ by writing ―I know that I need to add 2 to the number 4 to get 6. I also know that I need to add 20 to 30 to get 20 to get to 50. So, the answer is 22.‖ Is their strategy correct? Explain why or why not? / Example B
One of your classmates solved the problem 25 + 35 by adding 20 + 30 + 5 + 5. Is their strategy correct? Explain why or why not?

Des Moines Public Schools 2014-2015 Math Curriculum Guides Page | 1

Grade 2 – Chapter 5