Lesson 9

Classify Numbers

Est. Class Sessions: 1–2

Developing the Lesson

Part 1: What Number Am I

Distribute the folded What Number Am I Cards Masters you prepared to students. If there are not enough cards for every student, ask one or more students to share a card. If there are more cards than students, ask for volunteers to play a second card. It is important that every card is distributed.

Begin by explaining how the activity works.

Say:

X
  • I will start by reading the first clue.
  • Look at the left side of your card and think about whether the number on it matches the clue.
  • If it does, read the number from your card aloud. Then read the clue on the right side of your card aloud.
  • Even if you know the number that matches the clue, do not say it out loud unless it is on your card or unless I ask the class for help.

See the Sample Dialog for an example of how the activity might proceed.

The activity continues in this manner until all of the clues have been read and numbers have been found. The clues and answers are arranged so that the last student's clue leads to the teacher's answer. This signals the end of the activity.

X

This Sample Dialog models the What Number Am I game.

Teacher: Okay, I will start. [reads the right side of her card] I am a square number between 20 and 30. What number am I?

Jackie: Oh, that's me! [reads the left side of her card] I am 25.

Teacher: Good, Jackie. Can you read the clue on the right side now?

Linda: Okay. I am a twin prime number. My twin is 11. What number am I?

Teacher: Does anyone have a number on the left side of their card that is a twin prime with 11?

Teacher: [after pausing for ten seconds] Who remembers what a twin prime is?

Lee Yah: I do. It's a prime number that is right next to another prime number.

Teacher: What do you mean when you say “right next to”?

Lee Yah: Oh. I mean it's two away.

Teacher: Okay, so what numbers could be twin primes of 11?

Lee Yah: I guess 9 or 13, but 9 is 3 × 3, so it isn't a prime . . .

John: Oh, I think it's me. I am 13.

Teacher: Does everyone agree that 13 works?

Class: Yes.

Teacher: Good, John. Can you read your clue now?

John: I am a composite number. My prime factorization is 22 × 3. What number am I?

Student Guide:
Student Activity Book:
Master: