• Observe students as they complete the Expanded Form Worksheet (M-2-1-2_Expanded Form Worksheet and Key.docx).
• Observe students as they play I Have, Who Has Base-Ten (M-2-1-2_I Have, Who Has Base Ten.pdf).
• Observe student responses during Instructional Procedures.

Part 1

Begin the lesson by having students choral count as follows:

“Start at 200 and count forward by 100s.” Have students stop at 1000. (200, 300, 400, 500, 600, 700, 800, 900, 1,000)

“Start at 47 and count forward by 10s.” Have students stop at 127. (47, 57, 67, 77, 87, 97, 107, 117, 127)

“Start at 65 and count forward by 5s.” Have students stop at 115. (65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115)

“Start at 265 and count backward by 5s.” Have students stop at 230. (265, 260, 255, 250, 245, 240, 235, 230)

“Start at 362 and count backward by 10s.” Have students stop at 292. (362, 352, 342, 332, 322, 312, 302, 292)

“Start at 999 and count backward by 100s.” Have students stop at 99. (999, 899, 799, 699, 599, 499, 399, 299, 199, 99)

[Or you may also choose to begin the lesson by playing Cherry Pie (see Part 1 of Lesson 1).]

Part 2

Students stand in a circle. Distribute I Have, Who Has Base Ten cards (M-2-1-2_I Have, Who Has Base Ten.pdf) until all cards have been distributed. Some students may have more than one card. Have one student start by reading his/her card. Continue until all cards have been read.

“In the last lesson we represented numbers using number cards and base-ten blocks. For the number three hundred forty-two, we used the number cards 3, 4, and 2. We put the 3 in the hundreds place, the 4 in the tens place, and the 2 in the ones place. Like this.” Use the number cards (M-2-1-1_Number Cards.docx) and Place-Value Mat (M-2-1-1_Place-Value Mat.docx) to display the number three hundred forty-two. “When we write the number three hundred forty-two in standard form it looks like this.” Write 342 on the board. “We also used base-ten blocks to represent the number three hundred forty-two by using 3 flats, 4 longs, and 2 cubes. Like this.” Use base-ten blocks to display the number three hundred forty-two.

“In the number three hundred forty-two, the value of the 3 is 300. The value of the 4 is 40, and the value of the 2 is 2. Another way to display the number three hundred forty-two is to write the number in expanded form. When we write a number in expanded form, we write the number in a way that shows the value of each digit. Expanded form shows the number broken up into hundreds, tens, and ones. The number three hundred forty-two written in expanded form looks like this.” Write 300 + 40 + 2 on the board.

Distribute base-ten blocks. Have students use the base-ten blocks to show the number 126. Ask,

• “What is the value of the 1?” (100)
• “What is the value of the 2?” (20)
• “What is the value of the 6?” (6)
• “What would this number be in expanded form?” (100 + 20 + 6)

Repeat the above procedure with the following numbers. After students show the number using base-ten blocks, have them write the number in expanded form on their whiteboards.

• 461
• 320
• 208
• 524

Give each student a copy of the Expanded Form Worksheet (M-2-1-2_Expanded Form Worksheet and Key.docx). As students fill out the worksheet, move around the room observing and asking clarifying questions to evaluate which students understand expanded notation and which need additional exploration.

Extension:

• Routine: Partners play the Expanded Form Matching Game (M-2-1-2_Expanded Form Matching Game.docx). Partners play the Number-Cubes Game (M-2-1-2_The Number-Cubes Game.docx). Additional activities can be found under Related Resources.
• Small Group: Students will need base-ten blocks, index cards, pencil, whiteboard, whiteboard marker, and eraser. Follow these steps:

1.      “Get 3 flats, 4 longs, and 6 cubes.”
2.      “Count the flats and write the number on an index card.” (300)
3.      “Count the longs and write the number on an index card.” (40)
4.      “Count the cubes and write the number on an index card.” (6)
5.      “Arrange the index cards so they are in expanded form.” (300  40  6)
6.      “Use two index cards and write the plus symbol on each.” (+ +)
7.      “Put the plus symbols where they belong.” (300+40+6)
8.      “Write the number in expanded form on your whiteboard.” (300+40+6)

Repeat with the numbers 421, 293, 660, and 101.

• Expansion: Students can create a Number Book (M-2-1-2_Number Book.docx).