Lesson 3

10 Tens

Est. Class Sessions: 1–2

Summarizing the Lesson

Conclude the lesson by asking students to compare their original predictions about the total number of letters in the first names of everyone in the class with the actual number.

Ask questions similar to the following:

X
  • Were your predictions larger or smaller than the total?
  • Tell something new you learned about the number 100. (Possible responses: 100 is ten groups of ten; It is faster to count to 100 by ten than it is by ones.)
  • Is 100 larger or smaller than what you pictured before counting? (Possible response: I thought 100 was a really big number but it really is not.)

See the Sample Dialog for a discussion comparing predictions to the actual number.

X

In the following Sample Dialog, students describe insights gained about their predictions, perceptions of the quantity "100," and ways to count to 100.

Teacher: Let's talk about what we learned by counting all these letters. First, what about your predictions? Maya, was your prediction close to our total of 126?

Maya: No. I predicted 37. Our group was 18 so I thought 37 was a lot bigger. I found out 37 isn't big at all. I thought 100 was too big. I thought we'd never get that big.

Teacher: You're right that 37 is not very close to our total of 126. You knew that the number had to be a lot bigger than your 18 so you guessed a higher number. Not big enough, but your thinking was right on target. Anyone else?

Michael: I guessed really big. I said 500. We had 28 in our group so I thought it was going to be a thousand almost.

Teacher: Your reasoning was also good, Michael. You just went too high, just the opposite of Maya.

Luis: I guessed less than 100. I never knew 100 was so little before. I thought 100 was kind of big, but it's only 10 stacks. Ten isn't very much. That makes it seem littler. But I thought it was big.

Teacher: What made you think differently about 100?

Luis: I don't know. I just thought 100 was a lot of things, but this way it's only ten things.

Teacher: Ten stacks, yes, but each stack has ten cubes in it. Where else have you seen 100?

Nila: On the 100 Chart. It looks like so many numbers and my name doesn't even take up a row. So I thought 100 would be too big.

Teacher: That's interesting, Nila. What do you think about the way we counted to 100, skip counting by tens? Did it make it easier or harder?

Nila: A lot easier. I never thought we could do it. I thought it would take us forever to count. But just going 10, 20, 30 makes it go really fast and I didn't get mixed up.

Teacher: So you're saying that when we talk about whether 100 is big or not, it makes a difference how we are counting.

Jackie: Yeah. Counting 10 things is easy and fast. But counting 1, 2, 3, 4 is slow. And if you have a lot, it takes a long time. In kindergarten we counted 100 days and that was really long.

Teacher: So counting to 126 by ones would take a long time. Which way of counting do you think might cause more mistakes?

Nicholas: We would need to be careful. Counting by ones would be harder and we might make mistakes

Adventure Book:
Student Activity Book:
Master: