This lesson plan, adaptable for grades K-2 (intervention grades 3-5), centers around demo versions of Teachley Add and Subtract, interactive games featuring visual models of addition and subtraction strategies for solving math facts. These strategies include counting on, counting all (additon only), doubles (addition only), and counting back (subtraction only).  Teachley Add and Subtract promotes conceptual understanding and fact fluency for students who are just beginning to develop their addition and subtraction skills.

### Students will:

1. Use effective math strategies for addition, including counting and using doubles.
2. Use effective math strategies for subtraction, including counting back.
3. Express their mathematical thinking using the SnapThought® tool.

### Materials:

• Computers or other devices with Internet access
• Interactive whiteboard

### Preparation:

This lesson features addition and subtraction games developed by teachers and researchers at Teachley, an educational technology company.  The games teach effective math strategies and scaffold learning to promote conceptual understanding and fact fluency, so students not only learn to problem solve, but acquire new tools for learning math.

Preview and play Teachley Add and Subtract to plan how you will adapt it to your students’ needs, and to determine which math skill you want to target in today’s lesson: single-digit addition or subtraction.

For ideas on how to use SnapThought with this game, read Teachley: SnapThought Prompts for more information and specific SnapThought prompts to provide students during game play.

Depending on your classroom routines and available technology, you may want to consider these grouping options:

• 1:1 with students and devices
• Two to three students sharing one device and swapping ideas and the device back and forth
• Station model where small groups rotate through using the devices
Some things to know…
• The “Memory” button disappears after a few seconds. This is intentional as students should only use it when a fact is truly memorized.
• In the Add game, the “Doubles” tool is only active for “near doubles” problems, such as 3 + 4.
• To use the “Count On” tool in the Add game, first click the block you want to start with, then click the individual blocks for added support.
• In the Subtract game, if you click and hold a frog, you can slurp/spit more than one block at a time.

You might choose to build background knowledge or reinforce topics with these BrainPOP Jr. movies: Basic Adding, Counting On, Repeated Subtraction, Basic Subtraction, Making Equal Groups, Adding and Subtracting Tens, or Making Ten.

### Lesson Procedure:

1. Play one of the suggested BrainPOP Jr. movies (see Preparation) that is related to the Teachley game your students will play today (Add or Subtract) to build background or to make connections to prior knowledge.
2. Write a simple “almost doubles” problem on the board, such as 4 + 3 = and ask students to share how they would solve this problem. Or you can ask more specifically how they can use their doubles facts to solve this problem. Although some may have just memorized the fact, encourage others to describe how they might solve it if they didn’t know the answer. You can provide manipulatives and/or pencil and paper for students to show their strategies. If no one suggests the doubling strategy, be sure to model it and introduce “doubling” and/or “doubles” as a vocabulary word.
3. Project Teachley Add and Subtract for the class to see. Model for students how to navigate either the Add or Subtract game. Demonstrate or invite students to figure out how to use each of the strategy tools.  Be sure to point out the following:
• The “Memory” button stops flashing after a few seconds and then is not usable. This strategy is only for facts that have been memorized and therefore can be answered within seconds of seeing them.
• In the Add game, the “Doubles” tool is only active for near doubles problems, such as 3 + 4. Also note that when using the “Count On” tool, you must first click on the block you want to start with. Then you can click on the individual blocks for added support.
• To use the “Count On” tool in the Add game, first click the block you want to start with, then click the individual blocks for added support.
• In the Subtract game, if you click and hold a frog, you can slurp/spit more than one block at a time.
4. Depending on your students’ needs, you can play several rounds of the game as a whole class, inviting volunteers to come up and try the different strategies.
5. Now have students explore the game independently or in pairs, Allow 10-15 minutes for game play.
6. If students have individual logins through My BrainPOP, encourage them to use the SnapThought® tool to take snapshots during game play, and reflect on their strategies.
7. Circulate the room as students play, listening as they use or discuss their strategies, and provide help as needed.
8. Bring students back to a whole class discussion and have volunteers share their strategies for game play. Ask if they used any strategies that were new for them. Ask what they liked about the strategies they used and what they didn’t like.
9. Encourage students to revisit Teachley Add and Subtract throughout the school year to build fluency with addition and subtraction facts. NOTE: The full versions of the games are available at teachley.com and titled Addimals and Subtractimals.

### Extension Activities:

Have students challenge themselves to these offline activities after they play the game.