NC.2.NBT.1

Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones.

Unitize by making a hundred from a collection of ten tens.
Demonstrate that the numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds, with 0 tens and 0 ones.
Compose and decompose numbers using various groupings of hundreds, tens, and ones.

Step 1: Lesson Standards & Learning Goals

Unpacking Clarification

Unitize by making a hundred from a collection of ten tens.
- When students unitize (group) tens as a whole unit (called “a hundred”), they are able to count groups as though they were individual objects.
Demonstrate that numbers 100, 200, … refer to a number of hundreds with 0 tens and 0 ones.
- Students continue to apply their place value understanding from first grade as they are expected to build three-digit numbers that have only a non-zero number in the hundreds place. For example, 100 can be made of 10 groups of ten as well as 100 ones and 400 could be made of 4 hundreds or 40 tens or 400 ones.
Compose and decompose numbers using various groupings of hundreds, tens, and ones.
- For example, 125 can be made of 1 hundred, 2 tens, and 5 ones, OR the hundred block can be traded for 10 tens making the pile 12 tens and 5 ones. NOTE: This work should begin with exchanging (trading) 1 block for 10 of a smaller block before moving to extremely large groups of blocks that need to be exchanged. In all cases, students in second grade are only expected to exchange (trade) between one place value.

NOTE:

Students group objects as they count using both groupable manipulatives (i.e., materials that can be grouped, snapped, or connected to make a ten or hundred) and pre-grouped manipulatives (i.e., materials like base ten blocks, ten frame cards, and bean sticks, which must be traded to make a ten or hundred). The use of coins and money in place value is not developmentally appropriate since coins are not proportional (e.g., a dime is not 10 times bigger than a penny).

Through use of manipulatives and pictorial representations, students make a connection between the written three-digit numbers and hundreds, tens, and ones. Understanding the value of the digits goes beyond simply telling the number of hundreds or tens. Second graders who truly understand the position and place value of the digits are also able to confidently model the number with some type of visual representation. Others who seem like they know, because they can state which number is in the tens place, may not truly know what each digit represents.

Sample Essential Questions

What does a digit’s position in a number tell about its value?

How can tens be grouped as hundreds?

Explain and show one hundred as 10 tens using manipulatives, base ten blocks, or drawings.

Vocabulary

Base ten
Compose
Collection
Decompose
Digit
Group
Hundreds
Numeral
Manipulative
Ones
Place value
Tens
Unitize
Whole numbers

Students will be able to...

Unitize (Group) objects by making a hundred from a collection of ten tens.
Demonstrate that the numbers 100, 200, 300, 400, 500, 600, 700, 800, 900 refer to one, two, three, four, five, six, seven, eight, or nine hundreds, with 0 tens and 0 ones.
Compose and decompose numbers using various groupings of hundreds, tens, and ones.
Make connections between manipulatives/representations to the written number.

Students will know...

The value of a digit in a number is determined by the place value of the digit.
The three digits of a three-digit number represent amounts of hundreds, tens, and ones.
10 ones can be bundled and renamed as 1 ten, 10 tens can be bundled and renamed as 1 hundred.
Our number system is based on groups of ten. Whenever we get 10 in one place, we move to the next greater place value.

Step 2: Assessment