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Lesson excerpt:

NC Mathematics Standard(s): Understand place value.

NC.1.NBT.2 Understand that the two digits of a two-digit number represent amounts of tens and ones.

• Unitize by making a ten from a collection of ten ones.

• Model the numbers from 11 to 19 as composed of a ten and one, two, three, four, five, six, seven, eight, or nine ones.

• Demonstrate that the numbers 10, 20, 30, 40, 50, 60, 70, 80, 90 refer to one, two, three, four, five, six, seven, eight, or

nine tens, with 0 ones.

Additional/Supporting Standards: Understand place value.

NC.1.NBT.3 Compare two two-digit numbers based on the value of the tens and ones digits, recording the results of comparisons with the symbols >, =, and <.

Standards for Mathematical Practice:

2.  Reason abstractly and quantitatively.

3.    Construct viable arguments and critique the reasoning of others.

4.    Model with mathematics.

5.    Use appropriate tools strategically.

6.    Attend to precision.

7.    Look for make use of structure.

Student Outcomes:

·       I can compare numbers up to 99.

·       I can use mathematical words to compare the values of two numbers.

·       I can build numbers showing how many 10’s and 1’s compose a given number up to 99.

Materials:

·       Tall Towers game board for each pair of players

·       A deck with three sets of cards numbered 0-9 for each pair of players

·       Connecting cubes (2 sets of 100 per pair of students)

·       Markers (20 beans, two-color counters, or cubes per pair of students)

Advance Preparation:

·       Reproduce game board for each pair of partners.

·       Reproduce a deck with three sets of cards numbered 0-9 for each pair of players.

·       The teacher needs to assess the students’ mathematical understanding of the values of two digit numbers.

·       Prepare a list of names for working pairs of students.

  Directions:

1.      The teacher will model with the class how to draw two number cards and make the number that is greater. Example: If 1 and 5 are drawn the student could make a 15 or 51. 51 has 5 tens and 1 ones and 15 has 1 ten and 5 ones. 51 is greater than 15 so 51 is the number used. The two players agree that the greater number has been made.

2.      The teacher will discuss with the class the procedures of building numbers with connecting cubes to show 10’s and 1’s.

3.      The teacher will draw two number cards and the students will model the greater number that can be made with the two number cards with the connecting cubes.  Repeat again.

4.      The teacher will model the “math talk” for comparing the two numbers. The teacher may need to review “math talk” procedures such as watching and listening to each other and showing respect.

5.      Organize students in pairs.

6.      Each pair of players has a Tall Towers game board, a deck of number cards that has been shuffled and markers (beans, two-color counters, cubes).

7.      Player 1 draws two number cards and shows the number that is greater after having a “math talk” with his/her partner.

8.      Player 1 uses connecting cubes to represent the number showing 10’s and 1’s.

9.      Player 2 repeats what player 1 has done.

10.  The players will prove which number is greater during their “math talk”. The player with the greater number places a marker on his/her tower.

Example of a “math talk”:  Partner 1 says, “I have 61. 61 has 6 tens and 1 one.”

Partner 2 says, “I have 67. 67 has 6 tens and 7 ones.” Partner 1 says, “We both have 6 tens.”

Partner 2 says, “But I have 7 ones and you have 1 one. So 67 is greater than 61.  I get to put a marker on my tower.”

11.  The first player to earn 10 markers on his/her tower is the winner.

Questions to Pose:

As students play the game:

·   How do you know that the number you made with your two number cards is the greater number?

·   What mathematical strategy did you and your partner use to determine which number is greater?

·   Who won?  How did you determine that?

Possible Misconceptions/Suggestions:

Special Notes:

This game is played after students have an understanding of place value for tens and ones and numerous experiences verbally comparing two sets of objects using comparison vocabulary.

Solutions:

Students’ finished game boards will vary.