Lesson 3: Tens

Getting Started

Questions to Explore

  • How does place value work?
  • How can we use place value patterns to name, create, and compare large numbers?

Skills

  • Count to 120, starting at any number less than 120. In this range, read and write numerals and represent a number of objects with a written numeral
  • Understand 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 (and 0 ones)
  • Understand that 10 can be thought of as a bundle of ten ones, called a "ten"

Materials

  • "My Number Grid" page from Lesson 1
  • A Fair Bear Share by Stuart J. Murphy
  • abacus (kit)
  • base-10 blocks (kit)
  • blank paper
  • fine point dry-erase marker (kit)
  • laminated place value mat (kit)
  • whiteboard (kit)

Introduction

Materials: "My Number Grid" page from Lesson 1, fine point dry-erase marker (kit), whiteboard (kit)
Give your child the whiteboard and a dry-erase marker, and ask him to write numbers as you read the following clues. Read the clues aloud more than once.
  • A one-digit number that is greater than 6 and less than 8 (7)
  • A one-digit number that is less than 5 and greater than 3 (4)
  • A two-digit number that has the digits 3 and 5 and is less than 40 (35)
  • A two-digit number that has the digits 4 and 2 and is greater than 30 (42)
Allow him to look at the "My Number Grid" sheet as needed. Once he's written each number, let him check it as you read the clue one more time.
Reading and Questions
Materials: A Fair Bear Share by Stuart J. Murphy
Read aloud A Fair Bear Share by Stuart J. Murphy. As you read the story, ask your child to count the nuts, berries, and seeds that the bears collect to show that there are groups of tens and groups of ones. When you've finished the story, pose the following questions:
Questions
  1. How is the bears' trick for counting like using base-10 blocks and the abacus?
    they are making groups of 10
  2. Why do you think it's a good idea to count groups of 10?
    it's a faster way to count than counting by ones
  3. If you collected 15 berries, how many groups of 10 would you have? How many berries would be left over?
    1 group of 10, 5 berries left over
  4. If you collected 20 berries, how many groups of 10 would you have?
    2 groups of 10