## Friday, December 4, 2015

### Riddles in Math - Solving and Creating

This week in math, we did cube riddles. Children need many opportunities to:

* build logical reasoning skills
* make conjectures based on evidence
* practice math skills like "more than", "less than", and fractions

I prepared several small bags filled with different combinations of yellow, blue, red, and green cubes. For a couple days, children in teams tried (and succeeded) to figure what was in my bag by the clues I gave them, one by one. Each time I gave a clue, they worked out a possible solution using the cubes on their work areas. By the time I got to the last clue, there was only one possible solution.

Here's an example:
First clue: There are twelve cubes in my bag. (Students took 12 random cubes from their bucket.)
Second clue: The cubes are of four different colors (If students used less that four colors, they fixed their group to fit.)
Third clue: Three-twelfths of the cubes in my bag are blue.
Fourth: There is one more red that blue.
Fifth: There is one more yellow than green.

By the fifth clue, students showed me their cubes (3 blues, 4 reds, 3 yellow, 2 green) and I showed them what was hidden in my bag (the same!).

Then it was their turn.

Students definitely found SOLVING these riddles easier than writing them. They soon realized that they needed to take special care to see that the clues provided enough information to lead to only one answer. As they tested them out on each other, several groups had to go back and add another clue or two. They may also realize that the ORDER in which the clues are presented or used can affect the difficulty of the riddles.

This was active and engaged learning at its best - partners worked so well together, and both solving and making tricky puzzles was found to be intensely satisfying. Logical thinking underlies much of human activity, so it is crucial to give young students as much fun practice as possible.