Lesson 17

This warm-up prompts students to compare four comparison statements. It gives the teacher an opportunity to hear how students use terminology and talk about characteristics of the items in comparison. During the synthesis, ask students to explain the meaning of any terminology they use, such as comparing, greater than, and less than.

• Groups of 2
• Display the image.
• “Pick one that doesn’t belong. Be ready to share why it doesn’t belong.”
• 1 minute: quiet think time

• “Discuss your thinking with your partner.”
• 2–3 minutes: partner discussion
• Share and record responses.

• “How do you know that C is false?” (35 isn't less than 20 because 35 has 3 tens and 20 only has 2 tens.)
• “What could you change about C to make it true?” (Use the greater than symbol or switch the symbol around.)

The purpose of this activity is for students to compare numbers represented in different ways. Students place the numbers in order from least to greatest. Students may create alternate representations for each number in order to compare them. For example, students may represent each number with a drawing, or write the two-digit number that matches each card (MP2).

• Create a set of cards from the blackline master for each group of 2. 

• Groups of 2
• Give each group a set of cards and access to connecting cubes in towers of 10 and singles.
• Display the image in the student book.
• “Talk with your partner and decide how to order these cards from least to greatest.”
• 2 minutes: partner discussion
• Share and record responses.

• “You will compare numbers and put them in order from least to greatest. Each set has 4 numbers. Start by finding all the cards that have an A on them. Once you have them in order, write them in order on your recording sheet. Then look for the cards that have a B on them and do the same thing. Be ready to share your thinking.”
• 10 minutes: partner discussion
• Monitor for students who:
  • make a base-ten drawing for each number and compare the tens, then ones if needed
  • write each two-digit number and compare the tens, then ones if needed

• Display set A.
• Invite previously identified students to share.
• “How are these methods the same?” (They both showed the tens and ones. They both compared tens first.)

The purpose of this activity is for students to compare numbers less than 99 to the benchmark numbers 5, 10, 50, and 99.

Students may use a variety of methods, including considering the relative magnitude of numbers (for example, 49 is one away from 50), the value of the tens and ones (for example, 22 goes after 10 because 2 tens is more than 1 ten), and counting (for example, I know 97, 98, 99) to put the numbers in order. The emphasis is on the order of the numbers rather than the exact placement since this is not a number line. During the synthesis, students share how they ordered the numbers.

• Groups of 2
• Display the list of numbers in order from the student workbook.
• “What do you notice? What do you wonder?” (I notice that the numbers go in order. The number 1 is smallest and 99 is the largest. Why are these numbers in this list? Will we add numbers to this list?)
• 1 minute: quiet think time
• 1 minute: partner discussion
• Share responses.

• Read the task statement.
• 10 minutes: partner work time

• Display the list of given numbers.
• Invite students to share different methods for determining where to place each number.
• As students share, fill in each number in the correct order.