Lesson 8 Ten as a Unit

    • Let’s explore teen numbers.

Warm-up Which One Doesn’t Belong: Groups of 10

Which one doesn’t belong?

  1. Red counters, 10, scattered.
  2. Red connecting cubes, 9.
  3. Tower of 10 red connecting cubes.
  4. Ten frame, full. Red, 5 counters. Yellow, 5 counters.

Activity 1 Counting Collections: Count and Show How Many

Your job is to figure out how many cubes are in the bag.

Activity 2 Building Teen Numbers

  1. Connecting cubes. 1 tower of 10. 4 single cubes.

    Choose 4 numbers to represent.
    Circle them.

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    Use connecting cubes to show each number like Clare did.

  2. What did you notice as you were showing each number?

Practice Problem

Problem 1

  1. How many cubes are there?
    How do you see them?

    Connecting cubes. 1 tower of 10 cubes. 7 single cubes.

  2. Show 14 with connecting cubes.