# Lesson 12 Subtract From a Teen Number

Let’s subtract and add within 20.

## Warm-up Choral Count: By Ten

Count by 10, starting at 2.

What patterns do you see?

## Activity 1 Noah’s Collection

Noah likes to collect game pieces.

He has 19 game pieces arranged like this in his bin.

He takes out 8 game pieces to play with.

How many game pieces are left in the bin?

Show your thinking using drawings, numbers, or words.

Equation:

## Activity 2 Addition and Subtraction Equations With Teen Numbers

Find the number that makes each equation true.

Be ready to explain your thinking in a way that others will understand.

## Activity 3 Introduce Shake and Spill, Cover

## Practice Problem

## Problem 1

Find the number that makes each equation true.