In this unit, students will deepen their understanding that groups of tens and ones compose larger numbers. They will recognize the meaning behind numerical representation, and they will use this understanding to compare twodigit numbers in terms of “greater than” or “less than.
Key Concepts:
 When we count to 120, we use tens and ones in the same way as when we count to 20.
 The first digit of a twodigit number tells us how many tens there are, and the second digit tells us how many ones there are.
 Understanding the structure of the place value system allows us to determine whether one number within (100) is greater than, less than, or equal to another number.
Prior Knowledge Needed:
 Comparing numbers. (Grade K, Unit 9; K.CC.C.6)
 Counting to 100 by 10s and 1s. (Grade K, Unit 13; K.CC.A2)
 Rote counting and understanding amount counted; (Grade K, Unit 1; K.CC.A.1)
 Developing foundations of place value. (Grade K, Unit 14; K.NBT.A.1)
Units on the Horizon:
 Using place value to add and subtract twodigit numbers (Grade 2, Unit 1)
 Understanding threedigit numbers (Grade 2, Unit 6)
 Applying strategies to add and subtract within 1000 (Grade 2, Unit 11)
Lessons

Lesson objective: Understand that when we count to 120, we use number patterns in the same way as when we count to 20. Students bring prior knowledge of the counting sequence from K.CC.A1 and K.CC.A2. This prior knowledge is extended to larger numbers a...

Lesson objective: Extend counting sequence to 120. This lesson helps to build fluency with counting to 120. Number charts and number lines are used here because it supports recognition of number patterns. This work develops students' understanding that ...

Lesson objective: Recognize the amount of tens and ones in a twodigit number. Students bring prior knowledge of place value from K.NBT.A.1. This prior knowledge is extended to larger twodigit numbers as students recognize the amount of tens and ones t...

Lesson objective: Identify the tens and ones that make twodigit numbers. This lesson helps to build procedural skill with composing and decomposing twodigit numbers with/into their component tens and ones. Base ten blocks are used here because it supp...

Lesson objective: Compose twodigit numbers using component tens and ones. This lesson helps to build procedural skill with composing twodigit numbers with component tens and ones. Baseten blocks are used here because it supports understanding of the ...

Lesson objective: Apply knowledge of place value to compose twodigit numbers. This lesson provides an opportunity for students to apply their knowledge and understanding of placevalue to a mathematical situation. Students are asked to represent twodi...

Lesson objective: Compare the value of twodigit numbers using understanding of place value. Students bring prior knowledge of comparing numbers from K.CC.C.6. This prior knowledge is extended to twodigit numbers as students compare the value of twodi...

Lesson objective: Compare twodigit numbers using phrases like "is greater than," "is less than," "is equal to". This lesson helps to build fluency with comparing twodigit numbers. Baseten blocks and arrow cards are used to support understanding of ho...

Lesson objective: Compare twodigit numbers using place value. This lesson helps to build procedural skill in comparing twodigit numbers using place value understandings. Counters are used to support understanding of the quanitites that are represented...

Lesson objective: Practice using knowledge of placevalue to comparing twodigit numbers. This lesson provides an opportunity for students to practice using their understanding of placevalue to a mathematical situation. Students are asked to play a gam...