Math Background

Lesson: Place Value to 100
Introducing the Concept

Place value is the basis for your children's understanding of numbers and how numbers are related to each other. It is essential to reading, writing, and operating with numbers of all sizes. Understanding place value helps children recognize patterns in numbers, which enables them to better understand the values that digits hold in various places. As your children develop the understanding of place value to 100, they will then venture into greater numbers and into Place Value to 1,000. Having a strong foundation for place value to 100 will prepare your children for the greater numbers they will encounter later in the year.

Materials: connecting cubes (up to 100 per child or pair), hundred chart, Learning Tool 3 for each child or pair of children.

Preparation: Have a bag of cubes, a hundred chart (Learning Tool 7), and a tens and ones chart (Learning Tool 3) ready for each child. Give each child the materials and have them set aside the hundred chart for use later.

Prerequisite Skills and Concepts: Children should know how to count to 100 and read number words.

  • Write the wordthirty-six on the board.
  • Ask: Who can come up and write the numeral for this number word on the board?
    Invite a student to come up and write 36 on the board.
  • Ask: Can anyone think of how we can show 36 with these cubes?
    Have 40 cubes available.
  • Say: I have a way that we can group these cubes so that it is easier for us to count. I will make groups of ten cubes so that we can count them by ten.
    Make 3 groups of ten cubes.
    There are 6 left over, so I will just let them be single cubes.
  • Ask: How many groups of ten cubes did I make? (3)
    How many were left over? (6)
  • Say: We know we can write this number as thirty-six, or 36, but we can also write this number as 3 tens 6 ones. The tens tell us how many groups of ten there are (hold up the tens), and the ones tell us how many single cubes are left over (hold up the ones). Starting from the left, the tens go with the first numeral in a two-digit number (circle the 3), and the ones go with the second numeral in a two-digit number (circle the 6).
  • Ask: How could we write 75 as tens and ones?
    Allow a student to come up and write 7 tens 5 ones.
  • Say: Correct. Seventy-five tells us there are 7 tens and 5 ones.
  • Ask: Who can show this with the connecting cubes?
    Have a student come up and make 7 tens and 5 ones.
  • Say: Take out your workmat that has Tens and Ones at the top, and your bag of connecting cubes. We are going to model numbers on this mat so that we can see the tens and ones. Write the number 42 on the board. Use your cubes to show this number as tens and ones on your workmat.
    Circulate to see that children are making 4 tens and 2 ones.
  • Ask: Who can tell me how many tens you have? (4) How many ones do you have? (2)

    Repeat this process with various numbers until children demonstrate an understanding of place value. Be sure to help them connect the models to the words and numerals represented.

  • Say: Take out your hundred chart. I am going to say numbers, and I want you to use your red cubes to cover the numbers I say. Your hundred chart shows all of the numbers from 1 to 100 in order. There are many patterns on the hundred chart; today we are just going to look at the patterns of tens and ones.
  • Say: Look at your hundred chart. Look for the numbers that have a 4 in the tens place. Cover all of these numbers with red cubes.
    Circulate to see that children are covering all of the 40s with red cubes.
  • Ask: How many numbers did you cover with your cubes? (10) Who can read me the numbers he or she covered?
    Children should read all numbers from 40 to 49.

Repeat with other numbers, using tens or ones as the model. Have children find all of the numbers with a 7 in the ones place as well.

Houghton Mifflin Math Grade 2