Lesson 21 Compose and Decompose Numbers 11–19
Let’s make groups of 10.
Warm-up Which One Doesn’t Belong: Numbers 11–20
Which one doesn’t belong?
Activity 1 Where Will They Sit?
Activity 2 Finish the Equations
Kiran wrote equations to show the total number of students and how many students sat at the table and how many sat on the rug, but he didn’t finish the equations. Finish filling in each equation. You can use connecting cubes or two-color counters if they are helpful.
Activity 3 Centers: Choice Time
Choose a center.
Shake and Spill
Grab and Count
What’s Behind My Back?