Reading and writing the expanded form of numbers is introduced in this unit. Students will write multidigit numbers in expanded form as singledigit multiples of powers of ten. For example 643 = 600 + 40 + 3. Students should also understand multidigit numbers written in baseten notation, recognizing that the digits in each place represent amounts of thousands, hundreds, tens, or ones (e.g., 853 = 8 hundreds + 5 tens + 3 ones)
Key Concepts:
 Representing a whole number in different ways (including baseten numerals, number names, and expanded form) does not change its value.
 Understanding the structure of the place value system allows us to determine whether one number (within 1000) is greater than, less than, or equal to another number.
 Because 100 is greater than any quantity that can be represented by a 2digit number, we compare threedigit numbers by looking at the hundreds place first.
Prior Knowledge Needed:
 Compare two twodigit numbers; (Grade 1, Unit 13; 1.NBT.B.3)
 Understand that the three digits of a threedigit number represent the amount of hundreds, tens, and ones; (Grade 2, Unit 6; 2.NBT.A.1)
 Count to 120 starting at any number less than 120; (Grade 1, Unit 8; 1.NBT.A.1)
Units on the Horizon:
 Relating skip counting to mental addition and subtraction (Grade 2, Unit 8)
 Applying strategies to add and subtract within 1000 (Grade 2, Unit 11)
 Developing fluency in addition and subtraction (Grade 2, Unit 15)
 Developing strategies for addition and subtraction (Grade 3, Unit 3)
 Investigating patterns in number and operations (Grade 3, Unit 8)
Lessons

Lesson objective: Understand that representing a number in different ways (including base ten numerals, number names, and expanded form) does not change its value. Students bring prior knowledge that the three digits of a threedigit number represent th...

Lesson objective: Write numbers in expanded form as a sum of hundreds, tens, and ones. This lesson helps to build procedural skills with writing numbers in expanded form. Base ten blocks are used here because it supports understanding of how to decompos...

Lesson objective: Represent threedigit numbers using word form. This lesson helps to build procedural skills with writing threedigit numbers in word form. Base ten blocks and expanded notation are used here because they support understanding of the va...

Lesson objective: Apply knowledge of ways to name numbers. This lesson provides an opportunity for students to apply their knowledge and understanding of naming numbers to a mathematical situation. Students are asked to help the teacher complete her set...

Lesson objective: Apply our understanding of place value to compare threedigit numbers. Students bring prior knowledge of comparing twodigit numbers from 1.NBT.B.3. This prior knowledge is extended to threedigit numbers as students decompose threedi...

Lesson objective: Compare threedigit numbers using the structure of the place value system. This lesson helps to build fluency with comparing threedigit numbers. Sketches of base ten blocks and expanded form are used here because they support an under...

Lesson objective: Relate understanding of comparing numbers to ordering numbers. This lesson provides an opportunity for students to apply their knowledge and understanding of comparing threedigit numbers to a reallife situation. Students are asked to...

Lesson objective: Understand that we look to the hundreds place first when comparing threedigit numbers. Students bring prior knowledge of comparing twodigit numbers from 1.NBT.B.3. This prior knowledge is extended to comparing threedigit numbers as ...

Lesson objective: Compare numbers within 1000 using < , >, and = . This lesson helps to build fluency with comparing numbers within 1000. A place value chart is used here because it helps to build an understanding of place value at an abstract lev...

Lesson objective: Apply ability to compare threedigit numbers in solving a reallife problem. This lesson provides an opportunity for students to apply their knowledge and understanding of comparing threedigit numbers to a reallife situation. Student...