The purpose of this activity is for students to put numbers 1–20 in order.

• “How did you decide the order of the numbers?”
• Display numbers 1–12 in order.
• “Clare is putting the numbers in order. What would you say to her to help her find the number that comes next?” (Look for 13 because it comes after 12. Look for the number that has a 3 because the last number has a 2.)

The purpose of this activity is for students to use their knowledge of the number sequence to find the number that matches clues of 1 more and 1 less. Numbers 1–20 are displayed around the room. The numbers may be displayed in order, or the sequence of numbers can be mixed up for more of a challenge. The cards with number clues are included as a blackline master. Consider developing a signal, such as ringing a bell, so that students know when to move around the classroom. In the Activity Synthesis, students consider why there can be different clues that match a given number.

• Invite previously identified students to share what they noticed during the last round of number clues.
• “‘1 more than 15’ and ‘1 less than 17’ are both clues to 16.”
• “What are two different clues that could match the number 12?”

• Fewer, Same, More
• Math Fingers
• Tower Build
• Math Stories
• Which One?

To reinforce the learning of the lesson, students who choose the Fewer, Same, More center should use the less, same, more mat, with two sets of number cards 1–20. Students choose a number from one set of cards and place it at the top of the mat. Taking turns, each partner picks a card from the other set, decides if the number is less than, the same as, or more than the original amount, and places the card with the correct group on the mat.

• “In math class, it’s important to be able to explain your thinking. Describe a time when you were able to explain your ideas to other people in your class.”