## Contents

Connections to the 3 Curriculum Threads

Featured Standards for Mathematical Practice

## Connections to the 3 Curriculum Threads

Learn more about the 3 Curriculum Threads

**Operations: **In this unit, students are introduced to subtraction as taking apart or taking away. These separating situations are compared and contrasted to combining situations introduced in Unit 4.

**Number: **In the unit, students begin to develop an understanding that larger numbers are composed of smaller numbers. Numbers represent a quantity, the size of a set independent of what they objects are.

**Equivalence: **In this unit, students decompose numbers into different pairs of smaller numbers and discover that the total is still the same. They begin to consider organization and order, and the effect of these attributes on equivalence.The number of objects in a set is fixed no matter how it is arranged and counted, and different sets may have the same number of objects.

## Content Standards Addressed

### K.OA.A: Understand addition as putting together and adding to, and understand subtraction as taking apart and taking from.

**K.OA.A.1: **Represent addition and subtraction with objects, fingers, mental images, drawings, sounds (e.g., claps), acting out situations, verbal explanations, expressions, or equations.

**K.OA.A.2: **Solve addition and subtraction word problems, and add and subtract within 10, e.g., by using objects or drawings to represent the problem.

**K.OA.A.3: **Decompose numbers less than or equal to 10 into pairs in more than one way, e.g., by using objects or drawings, and record each decomposition by a drawing or equation (e.g., 5 = 2 + 3 and 5 = 4 + 1).

## Featured Standards for Mathematical Practice

**S.MP.1. Make sense of problems and persevere in solving them.** Students actively engage in problem solving around decomposition, equality, and operations. They develop positive attitudes, critical thinking, and sensemaking around the use of subtraction in real-world situations.

**S.MP.4. Model with mathematics.** Model with mathematics. By applying prior knowledge of addition as putting together and add to, students will model using the actions of taking apart and taking away. Students will use tools and manipulatives to show their thinking and understanding of subtraction. Students will use these tools to represent real-world problems.

**S.MP.5. Use appropriate tools strategically.** Use appropriate tools strategically. Students will begin to explain how their choice or use of tool or manipulative supports their math thinking. The movement of these tools will support students building knowledge of subtraction as take apart or take away.

## Major Representations Used

Dot dice provide dot sets for subitization of one through six.

Five frames have the same structure as ten frames; it takes two five frames to make a ten frame.Ten frame cards have the same structure as our place value system because every time the frame is filled, a ten is composed.

Five frames have the same structure as ten frames; it takes two five frames to make a ten frame.Ten frame cards have the same structure as our place value system because every time the frame is filled, a ten is composed.

Five frames have the same structure as ten frames; it takes two five frames to make a ten frame.Ten frame cards have the same structure as our place value system because every time the frame is filled, a ten is composed.

## Common Misconceptions

- Linking cubes are direct models for composing and decomposing quantity.
- Students may confuse the spread of the objects spatially as representing a larger number.