Lesson 1

Hundreds of Coins

Est. Class Sessions: 1

Summarizing the Lesson

Day 100. On the 100th day, students begin by adding one penny to each of the four jars and making the appropriate trades as they did for the first 99 days. Tell them that today, they will count the money in each of the four jars to see if each has the correct amount of money. Ask how much money should be in each jar. Since they have been adding pennies in increments of one penny per day, they should readily know that each jar contains the equivalent of 100 pennies, or $1.00.

Begin by discussing with the students the length of time for the project as a whole. Remind students of what the month and date was on Day 1. Have students tell the months that have elapsed since that date. If possible, show the intervening months on a calendar. Ask students how close their predictions were. Remind students that their predictions do not have to be exact to be close.

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In this dialog the teacher guides a discussion of efficient strategies for grouping and counting the coins in the jars.

Teacher: We have a lot of coins here. Let's discuss how we're going to count them. Who has an idea for how you can best count them?

Luis: I can just go 1, 2, 3, 4. Like that.

Teacher: Which coins will you count that way, by ones, Luis?

Luis: The pennies.

Teacher: Why would you count the pennies by ones?

Luis: Because each penny is just one.

Teacher: Okay, that makes sense. A penny is one cent, so we can count them by ones. What do the rest of you think? Do you think we should count them by ones like Luis does?

Jerome: That would take a long time. I think we should count them by tens.

Teacher: How would you do that Jerome?

Jerome: I would make little piles, with ten in each. Then I would go 10, 20, 30, 40 all the way.

Teacher: You'd skip count by tens?

Jerome: Yes. That would be faster.

Teacher: Shannon, would you count them Jerome's way or Luis' way?

Shannon: I think I would do Jerome's way. One time I tried to count a lot of pennies, and I counted them by ones. I got really mixed up, and I had to start over.

Teacher: Good point, Shannon. You think it might be easier to count them by tens, but if you wanted to, could you still count by ones? Would you get the same number?

Shannon: Yes, but it would be slow, and I might have to start over.

Teacher: How about the nickels? How can we find out how much the nickels are worth? Would counting by ones work for nickels?

Frank: I don't think you can. Because they are not one cent. They are five cents.

Teacher: So, if I said, 1, 2, 3, 4 [demonstrating with nickels], you don't think that would work.

Frank: No. Each time you say one, it's not really one, it's five cents.

Teacher: So how would you count the value of the nickels, Frank?

Frank: Skip counting. 5, 10, 15, 20, 25 …

Teacher: Let's do that. [Frank counts the value of the nickels by placing one nickel at a time on the display and counting by fives to 100. The class counts with him.] Is there another way to count the nickels as a way to check?

Michael: We can put two together to make 10¢. Then we can count by tens.

Teacher: That's a good idea, Michael. Then it might go faster. Irma, what do you think? Can you use Michael's strategy to find the value of the nickels? [Irma places the nickels in piles of two and the class counts in unison by 10s to 100.]

Teacher: Can you show me how the counting you just did is like the Nickel Chart? [Irma looks confused.] Show me a nickel on the Nickel Chart. [Irma points to the first circled coins.] Okay, now show me two nickels. [Irma points to the end of the first row.]

Irma: Oh, I see. Each row is like the piles we made of two nickels and the piles are 10¢ just like the rows. Then we can count by tens using the rows.

Teacher: What about the quarters? How should we count those?

Grace: Quarters are easy because there are only 4 of them. Four quarters is the same as one dollar. So it will be just one dollar.

Teacher: Class, what do you think of Grace's idea? Can we count the quarters that way?

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Use the Day 100 More Coins section of the Hundreds of Coins Assessment Masters to assess students' abilities to identify the relationship between pennies and nickels [E4] and find the value of a collection of pennies, nickels, dimes, and quarters [E5].

Then ask the students to consider how they will count the coins.

Ask:

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  • Will you group the coins before counting?
  • How will you group them?
  • Will you group all the coins the same way, e.g., pennies and quarters?

See the Sample Dialog in which the teacher helps students evaluate counting strategies.

Have groups of students count each of the collections of coins. The pennies will take longer to count, so assign more students to that group. Tell each group to preserve their groupings and report the total to the class. As each group reports the amount of money in its jar, write the total amount at the bottom of the appropriate chart. If any jar is found not to have $1.00 in it, have a different group of students recount the coins.

Adventure Book:
Student Activity Book:
Master: