The Teens

Est. Class Sessions: 1–2

Developing the Lesson

Part 1: Where Are the Teens?

Direct students' attention to the class number line. Point to the numbers 11–19 and ask students to name these numbers as you point to each one.

Ask:

What do you notice about these numbers and their names? What can you say about them? (They all have a one as the first digit; the second digit in each is the counting number; most end with a "teen" when we say it; for some we say a counting number and then add "teen," such as sixteen.)

Display the 100 Chart from the Student Activity Book Reference section.

Ask:

Where do we find these numbers on the 100 Chart? (the second row)
Which numbers do not say "teen" in their names? (eleven and twelve)

Display the Two Ten Frames Master.

Ask:

How can you show 11 on the ten frames? (One full ten frame, one space in the next ten frame.)

Show one full ten frame and a second ten frame with 6 marks or cubes.

Ask:

How would you write and say this number? (16, sixteen)

Tell the class that even though they already know a lot about the teens, they will be spending some time today thinking about "what makes a teen?" Students begin the What Makes a Teen? pages in their Student Activity Books.

Discuss the first row on the page.

What do you see in the first box of the first row? (2 ten frames, one is filled, one is empty)
How should you fill in the rest of the row? (1 ten, 0 ones left over, 10)

Make sure students understand the directions; then have them complete the pages. As students are working, give connecting cubes to students who appear to be finishing early, assign them each a number from 10 to 20, and ask them to represent that number using connecting cubes. Suggest that they use their completed pages to help, but do not give further direction.

As students complete their cube models, have them place the models on the ledge of the board in numerical order, as shown in Figure 2. Some students may have built a stack of ten and a shorter stack for the ones. Other students may have put all the cubes together in one long stack. When all the students have finished the pages, draw attention to the cube models as students have built them.

Say:

What patterns did you notice in your What Makes a Teen pages? (Each one had a full ten frame; from 11 on, they each had a full ten frame and some in the second ten frame, in order, 1, 2, 3, 4, etc.; the last one had two full ten frames.)
Do we have all these numbers represented on the ledge?
What's the smallest number on the ledge? (10)
What is the largest number? (20)
How are the numbers shown with cube models similar to the numbers shown with ten frames? How are they different? (The ones with a stack of ten and a short stack of the ones show the pattern of ten and ones left over; the others do not.)
How can we make the connecting cube models show the same pattern of ten and ones left over?

With each one of the models, ask the class how it can be reconfigured to make it show the ten and the ones left over. As students direct, break the ten off and place the short stack of ones next to it as in Figure 3. Above each model, write the Arabic numerals for the number and the spelling of the word, for example, "13 thirteen." Have the class say the numbers aloud as you write them.