To review the story and key concepts of this lesson, have students work in groups of four. Ask the student groups to discuss the special power of each superhero: Add Zero, Subtract Zero, Multiply by Zero, and Divide by Zero. Then assign each group member the role of one of the superheroes. Tell them their mission is to introduce themselves to the group and to explain their special power in their own words. Remind students to focus on the mathematical properties of adding, subtracting, multiplying, and dividing 0 in their discussions.
Next, tell the class to imagine that the superheroes created Function Machines. The machines match each hero's super power.
- If Add Zero made a Function Machine, give an example of an input number, an output number, and a number sentence. Explain the rule. (Responses will vary. Possible response: Input 100, output 100, 100 + 0 = 100; When you add 0 to a number, the result is the number you started with.)
- Do the same for Function Machines made by Subtract Zero, Multiply by Zero, and Divide by Zero.
- Who is the strongest member of the Cipher Force? Why? (Answers will vary.)
- At the end of the story, a new Cipher Force member is introduced. What could Zero the Digit's super power be when it comes to writing numbers? (Possible response: Zero the Digit is very important for his place-holding power. For example, he holds a place in between the hundreds and the ones in 203 so we can see that there are no tens. He makes it possible for us to tell 203 from 23.)
