Halloween Math Talk

I hope you had a fun Halloween!  Here is an idea for a math talk that I did yesterday with students.

First, let students know that you are going to put an image on the board, but only for a few seconds.  Their goal is to figure out "how many there are."  With only a few seconds, they won't have time to count them all individually.

Next, display this on the board for a few seconds… not long enough to count all the pumpkins.
Record answers before you reveal the image again.  The answer is 39.

Have students share how they got their answers.  If they got the wrong answer, they can share where they went wrong.  If they got it correct, they can share their strategy.  This is a good way to encourage the idea that there is more than one way to approach  problem.

Some ideas I heard in my classes:
1. Group the top left 12 and the bottom left is the same.  That makes 24, then count the remaining pumpkins to equal 39.
2. If there was a pumpkin in every "space" there would be 48 pumpkins.  There are 9 "missing," so subtract 9 from 48 to get 39.
3. Count by groups of 4.  There are 6 groups of 4 and 3 remaining, so 6x4 = 36, plus 3 gives you 39.

Of course if you want to try this idea, and Halloween is over, you could easily make one with another image for another holiday!

Now, of course I have to include a picture of my cute kiddo dressed up in her costume!
Happy Ladybug!


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