2nd Grade Unit 4: Using Place Value in Algebraic Reasoning

Unit Driving Question

How do we use equivalence to describe our world?

Essential Questions

1. How do we use math to describe our world?

2. How do numbers represent real-life situations?

3. How can we use patterns to understand properties in the number system?

Big Ideas

1. A relationship exists between number sentences and other representations of numbers.

2. Number sentences represent real-world situations.

3. Properties help us find unknown values in number sentences.

Base Ten Recognition Students can practice identifying base ten blocks, matching it to the standard form.

Maximum Capacity  Students practice estimation and mental math.

Virtual Base Ten Blocks

Splash Math Option to assign activities.  Free account comes with limited reports. Also free download on ipad. 

Launch Task

1 Lesson

• Tic Tac Toe Sums - Students not only build fluency but also are solving for the unknown in addition number sentences, from youcubed.org.

Big Ideas for Development Lessons

3 Weeks (approximately 1 week per big idea)

Big Idea 1: A relationship exists between number sentences and other representations of numbers.

Collaborative Engagement 

1. One up one down - The task is to find out what happens to the sum if you add 1 to one of the sevens and subtract 1 from the other seven (e.g., 8 + 6)

Key Resources 

1. Ten and Then Some - Students work in pairs to decide equivalences between number sentences and the sum of two values.
2.  Let’s Trade - Students make connections between different representations of subtraction problems.
3. Balancing Act - Students explore the relationship between weight on either side of a pan balance.
4. In Balance - Students explore equivalence using an online pan balance and shapes. 

Big Idea Formative Assessment

1.   Different but the Same- Students find different ways to express a number, using both addition and subtraction.

Evidence of Understanding

• Model equations using representations, such as a number line and objects

• Know the equal sign means “the same as”

Big Idea 2: Number sentences represent real-world situations.

Collaborative Engagement 

1. Parts Unknown Problem - Students complete and solve addition and subtraction number stories, from Open Middle. 

Key Resources

1. Balance the Cups  - Students use a scale to find a missing variable and create number sentences to describe the scale model. 
2. Ballast - Students balance both sides of equations to determine which of three addition problems are impossible to solve.
3. Saving Money 2 - Students use number sentences to represent how much money is needed to purchase items and how long it will take to purchase them. 

Big Idea Formative Assessment

1. Story Problems revisited  - Students solve and explain real-world situations.

Evidence of Understanding

• Create a number sentence to represent a real-world situation

• Create a real-world situation to represent a given equation

Big Idea 3: Properties help us find unknown values in number sentences.

Collaborative Engagement

1. Bears in Caves  - Students problem-solve to find an unknown-addend. 

Key Resources 

1. Shared Fruit - Students problem-solve to find an unknown number in a real-world situation.
2. Part-Part-Whole Cards - Students work with a partner to find the missing part to a number sentence.
3. I Have a Story, You Have a Story - Students will apply various problem-solving strategies as they create and solve more difficult story problems. 

Big Idea Formative Assessment

1. Horses Problem Solving Task - Students problem-solve to explain a real-world situation.

Evidence of Understanding

• Determine if a number sentence involving addition or subtraction is true or false

• Use the commutative and identity properties and number sense to find an unknown value in a number sentence

Unit Closure

1 Week (includes time for probes, re-engagement, and assessment)

1. Amazing Animal Athletes- Students use their skills to inquire, create, and solve problems to compare animals.