Operations and Algebraic ThinkingVideo Lessons 
Represent and solve problems involving addition and subtraction (major work)
Add and subtract within 20 (major work)

This lesson builds on students' prior knowledge of combinations of ten. Students will add within 20 by decomposing to make 10. The task challenges students to add by decomposed and recombined to make a ten as an addition strategy. The big idea focuses o...

Big Idea: Numbers can be decomposed and recombined different ways to add and subtract. Therefore, there are many solutions to the same problem. This lesson builds on students' understanding of composing and decomposing numbers as strategies to add and s...