## Saturday, February 11, 2012

### Counting by 2, 5, and 10

Day One: Count by 2

Over the weekend there was a lizard in the school! It was wandering around the school like it was looking for something. We’ve got to figure out the clues to find out what it was doing and why? To solve this mystery we’ll have to use some different counting techniques. We’ll have to count by 2’s, 5’s, and 10’s to decipher the clues. Let’s get started!
There were lizard tracks found around the school. The strange thing about this is that they were only in some rooms and not others. Here is a map of the school (distribute maps to each student). We will have to solve a math problem to find out if the lizard was in that room.
After students solve all of the problems, tell them that rooms with an EVEN answer are the rooms where footprints were found. Let’s count the rooms to figure this out. No footprints in room 1 – but yes in room 2. None in room 3 but yes in room 4. Is there a pattern here? Let’s count by 2’s and see if this follows the pattern.
If finish early – go around the group counting by 2’s. Have each student list the next multiple of 2. See how high you can go.

Day Two: Count by 5

So we know which rooms the lizard visited over the weekend. Let’s review the rooms he was in. (Count by 2’s to review) Look at the rooms again. We now know what rooms he was in, but what time was he in each room? Let’s look at the clocks in each of these rooms and figure out what time they show.
Distribute map #2 to each student. Students will count by 5’s to tell the time on each clock and write the time in the space provided.
Is there a time we see often? Maybe that time (1:40) means something special? Let’s keep it in mind this week and see if we can piece together the pieces of this puzzle.

Day Three: Count by 10

How many people did the lizard see over the past week? We believe he dropped something when he saw a student. So let’s look at how many items were found around the school. This will tell us how many students he saw. We’ve gathered them all and counted them. Dump 120 items (COUNTERS) on table and start counting by 1’s. Oh no. This is going to take us FOREVER! Is there a faster way? Lets group them into piles of 10 and then count them by 10’s! Do this as a group. When you are finished, you can try sorting the items into groups of 5’s and 2’s to review.

Day Four: Review

So let’s review what we’ve learned so far. The lizard was in which rooms? Review count by 2’s (I’m just curious – how high can we count by 2’s?). Good! We also know that the lizard appeared most often at 1:40. Let’s count by 5’s on our clock to get to 1:40. Review count by 5’s. (I’m just curious – how high can we count by 5’s?) We also found out that the lizard dropped something every time he saw someone at the school. Let’s review counting by 10’s to count how many items he dropped. Review count by 10’s. (I’m just curious – how high can we count by 10’s?)
Now wait a second! Maybe this lizard was trying to tell us something?? Maybe he was trying to tell us that we should deliver a special treat to 120 people at 1:40 today?? Let’s do it! There are about 120 people in the whole first grade! Should we give a small treat to each of the first grade students at 1:40?? Look at the clock and see how much time we have (REVIEW TIME). Dump out a bag of candies on the table and ask students to get in 4 groups – assign each group a class to get treats for. They can count by 2’s, 5’s, or 10’s to get the right number of treats for each first grade class. When they get them sorted and counted, deliver the treats to each class with the attached note.