# Lesson 2 Fluency Flip

Let’s add and subtract fluently.

## Warm-up True or False: Sums within 20

Decide if each statement true or false. Be prepared to explain your reasoning.

## Activity 1 Heads Up: Make 20

Directions:

Partner A holds a card on their forehead without looking.

Partner B names the number that you can add to the number on the card to get 20.

Partner A says the number on their card.

Record an equation to represent how you found the unknown addend.

my equations | my partner’s equations |
---|---|

## Activity 2 Number Mix Up

You are going to use your cards to complete number puzzles. You may only use numbers 0 through 9. You may only use each number one time to make all the equations true.