# Lesson 6 Center Day 1

Let’s add and subtract in center activities.

## Warm-up Number Talk: Teen Numbers, Two-digit Numbers

Find the value of each expression mentally.

## Activity 1 Revisit Number Puzzles, Within 20

We are going to play a game you may have played in first grade called Number Puzzles.

## Activity 2 Centers: Choice Time

Choose a center.

What’s Behind My Back?

How Close?

Number Puzzles