In this unit, students begin to form understandings of subtraction as both take apart and take from. Partpartwhole relationships in their contexts will extend their understanding of addition operations and link them to this new learning using subtraction operations. Students are likely to think that decomposition will produce a greater number of total objects. In the final four lessons, students decompose, add and subtract numbers to 5 to show conservation of the set is maintained even as the set is split into different pairs.
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Key Concepts:
 Subtraction can be understood as taking apart (Lesson 1).
 Subtraction can be understood as taking from (Lesson 4).
 The same number can be decomposed in more than one way (Lesson 7).
Prior Knowledge Needed:
 Conservation (Kindergarten, Unit 2, K.CC.B.4b)
 Written numeral recognition (Kindergarten, Unit 2, K.CC.A.3)
 Understand addition as putting together and adding to (Kindergarten, Unit 4, K.OA.1)
Units on the Horizon:
 Understanding addition and subtraction within 10 (Kindergarten, Unit 10).
 Composing ten (Kindergarten, Unit 10).
 Developing foundations of place value (Kindergarten, Unit 7).
 Solving problems and demonstrating fluency within 5 (Kindergarten, Unit 8).
Lessons

Lesson objective: Understand that numbers can be taken apart. Students bring prior knowledge of addition from K.OA.A.1 and K.OA.A.2. This prior knowledge is extended to contrast the new concept of subtraction as students learn that number can both be co...

Lesson objective: Decompose numbers within 5 to understand subtraction as "take apart". This lesson helps to build procedural skill by decomposing totals into number partners. Number bonds and five frames are used here because they support student organ...

Lesson objective: Solve problems by taking apart. This lesson provides an opportunity for students to apply their knowledge and understanding of decomposition to a reallife situation. Students are asked to create at least two combinations of tomato pla...

Lesson objective: Understand that taking from a total is a way to model subtraction. Students bring prior knowledge of adding to a number from previous experience with K.OA.A.1 and K.OA.A.2. This prior knowledge is extended to contrast the new concept o...

Lesson objective: Subtract by taking from a total within 5. This lesson helps to build procedural skill with subtraction within 5. Drawings and number paths are used here because they highlight the contrast of the orginal set with the remaining amount a...

Lesson objective: Solve problems by taking from. This lesson provides an opportunity for students to apply their knowledge and understanding of subtraction as removal to a reallife situation. Students are asked to select at least one recess activity to...

Lesson objective: Understand that a number can be decomposed or taken apart in more than one way. Students bring prior knowledge of decomposition from previous work with K.OA.A.1 and K.OA.A.2. This prior knowledge is extended to include a more broad def...

Lesson objective: Decompose to find more than one set of number partners for the same total. This lesson helps to build procedural skill with decomposition of numbers up to five. Number bonds and five frames are used here because they support structure ...

Lesson objective: Find number partners by decomposing and recomposing five. This lesson helps to build procedural skill with decomposition. A math rack is used here because it supports subitization of the smaller parts of a total and organizes these pie...

Lesson objective: Connect decomposing a total into number partners to patterns found in these pairs. This lesson provides an opportunity for students to apply their knowledge and understanding of decomposition to a mathematical situation. Students are a...