The teacher presents the first problem:
is it possible to place each number 1 through 6 around the outside of a triangle and make the numbers on each side add up to 10? With the students help, the teacher tries the problem out.
Teacher: Let’s see… I could put the 6 here, and the 3 here.
Then what would need to go in this spot?
[calls on a student]
Student: It would have to be a 1, since 6 + 3 = 9, and that’s 1 away from 10.
Teacher: So now I still have a 2, 4 and 5 to place. Where should I put them?
Student: Put the 4 on the top. Then 4 + 6 = 10.
Teacher: All right. Then what goes in the circle on the right?
I’ve got a 4 and a 1 on that side already.
What plus four plus one equals ten?
Think about it, then share with your neighbor what you think the answer is, and explain why you think that’s right. [Kids pair andshare.]
Student: It has to be a 5, since 4 + 1 = 5, and 5 plus 5 is 10.
Teacher: Then what goes in the last spot?
Student: Well… 2. But that can’t be right!
Teacher: Hmmm. You’re right. 6 + 2 + 4 = 12, so we made a mistake on that side.
We need to move something around.
Maybe putting the 6 and 3 where I did to start was a mistake.
What else could I have tried?
Student: Maybe you should have moved the 3 to the top.
Student: You could have put the 1 in the corner to start.
Teacher: Maybe some of those will work. Maybe they won’t.
We won’t know until we try them out.
I’m going to give you the chance to do that now.
You can take a worksheet or draw your own, and see if you can solve the Magic Triangle puzzle.
It is possible! Once you get an answer, there are some even trickier ones to try out. Let’s go!