10-23-06

Introduce penny strips:

“We have been talking a lot about groups: a group of 5, a group of 6, a group of 8. Today we are going to make groups of ten. Remember we were in groups of 10 on our field trip last week? Groups of 10 are especially important because our numbers use groups of 10. Also, our money uses groups of 10. Remember that 10 is the //most important number//. We are going to find out how many groups of 10 pennies we have. I will show you with my pennies, then you will try it with your pennies. We are going to use these penny strips to help us collect 10 pennies. On each strip you can put 10 pennies.”

Estimate how many pennies there are and write estimates down on the board.

“Now we’ll find out how many I really have. We will use this penny strip to help us see when we have 10. I will put my pennies on top of the pennies on this strip. Let’s count how many pennies are on the strip. When I cover all the pennies on the strip, I will have 10 pennies, one group of ten pennies and no extras. The pennies that don’t fit in the group of 10 are the extras. So let’s see how many groups of 10 I have and how many extras. How many strips can I fill?”

Have a child come fill up the strip.

“So, now we have one group of 10. Let’s see if we can make another group of 10.”

Another child comes up.

“How many groups of 10 do I have? How many pennies do we have so far?” Count by tens. “So we have 2 groups of 10 and 10, 20 pennies. How many extras are there? 1, 2, 3, 4. Is that enough to make another group of 10? So how many groups of 10 do we have? (write it on board). And how many extras? (write it on board). Let’s count the pennies. 2 groups of 10 and 4 extras equals: 10, 20, 21, 22, 23, 24 pennies. Let’s count by ones to make sure.”

“Now look how we write the number 24. We write a 2 because we have 2 groups of 10, and a 4 because we have 4 extras, and that is how we write 24.”

Try again as a whole class in 2 groups of 10.

Then have each group work in pairs to do the same with cupfuls of pennies, using penny strips worksheet.

//Extension for kids who get it quickly, if necessary: give them numbers to make on the penny strips and they show on paper how they did it.//

End: Play Snap It orCounters in a Cup? Depending on how things are going and if there is time. 10:40: whole-class story problem.