In this culminating unit, students apply understandings gained throughout the entire year to demonstrate fluency in addition and subtraction. They practice solving various problem types, including adding to, taking from, putting together/taking apart, and comparison, with the unknown quantity in different positions. Students are given opportunities to select, justify and explain their strategies orally and pictorially as they make meaning of word problems. Students continue to build fluency to add and subtract within 20 by using known addition and subtraction facts to solve complex problems.
Unit-at-a-glance
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Key concept: The meaning of addition and subtraction do not change no matter which tools we are using. |
Key concept:We can solve many kinds of problems using addition and subtraction. |
Key concept: We can use addition and subtraction facts we already know to help us solve addition and subtraction problems we haven't seen before. |
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| Suggested pacing |
Days 1-3 |
Days 4-7 |
Days 8-10 |
| Suggested class plan |
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Additional unit information
Prior Knowledge Needed:
- Understand addition as “putting together and adding to” and subtraction as “taking apart and taking from”; (Grade K, Unit 6; K.OA)
- Represent and solve addition and subtraction problems of all types; (Grade 1, Unit 9; 1.OA.A.1)
- Add and subtract within 20 using strategies such as counting on; making ten; decomposing a number leading to a ten, and using the relationship between addition and subtraction; (Grade 1, Unit 9; 1.OA.A.C.6)
- Work with addition and subtraction equations; (Grade 1, Unit 9; 1.OA.D.7)
- Associative and Commutative Properties; (Grade 1, Unit 15; 1.OA.B.3)
Units on the Horizon:
- Adding and subtracting within 100 (Grade 2, Unit 1)
- Relating skip counting to mental addition and subtraction (Grade 2, Unit 8)