1. Begin by displaying an anchor chart with two sections: addition and subtraction. Ask students to guess a variety of combinations of numbers they can add (e.g. 3 + 6, 12 + 8) or subtract (e.g. 18 - 11, 9 - 5). Write each combination on the chart.
2. Give each student a set of number cards (1-20) and explain that the object of the game is to match the number combinations on the anchor chart.
3. Instruct students to create their own number combinations and show them to a neighboring classmate. The first person to correctly identify the combination receives a point.
4. Provide guided practice for more challenging combinations by having students work with a partner.
5. Once students have had sufficient practice, play a game called "Flawless Fact Fluency." This game is played in teams of two. Each student is dealt four cards, which they use to match number combinations. The team with the most points after five rounds wins the game!
6. End the lesson by having students summarize what they learned. Encourage them to practice their fact fluency skills on their own at home.