Curriculum Library

Operations & Algebraic Thinking Unit 4: Add and Subtract Within 20

Key Concept: Strategies can help to add and subtract quantities efficiently.

Lesson Sequences

O.4-1-4 Double Fact Strategies to 18  |
View Lesson Opener Discover & Discuss (5-10 min)
View Guided Lesson Students use double facts within 18 to efficiently determine the sums of double plus one facts.  (12-20 min)
View Lesson Closer Math Musings (5-8 min)
O.4-1-6 Decompose to Subtract Within 20  |
View Teacher-Facilitated Lesson Students apply their understanding of decomposition to make a ten when subtracting within 20. (35-45 min)