Lesson 5

The purpose of this lesson is for students to put numbers 1–20 in order and use their knowledge of the count sequence to identify one more or one less than a given number.

In a previous lesson, students initially counted out objects and added or subtracted one object to determine one more or one less than a given number. In this lesson, students continue working on identifying one more and one less than a given number up to 20 without objects and relating one more and one less to the count sequence (MP8). This lesson is optional because the standards do not require students to compare groups of objects or written numbers beyond 10.

If students need additional support with the concepts in this lesson, refer back to Unit 6, Section B in the curriculum materials.

• Create a set of cards from the blackline master for each group of 4.

• Each group of 2 needs one card from the blackline master.
• Display large numbers 1 to 20 around the room. The numbers may be displayed in order, or the sequence of numbers can be mixed up for more of a challenge.

• Gather materials from:
  • Less, Same, More
  • Math Fingers
  • Tower Build
  • Math Stories
  • Which One

Were you able to circulate and hear student thinking while students worked together in the second activity? If so, what routines or structures helped students work independently? If not, what routines or structures can you establish to ensure that you are able to circulate and talk to students as they work in groups?