This time we did puzzles. Specifically, we looked at ALGEBRAIC puzzles, where we had to figure out which numbers belonged to each letter (VARIABLE).
Some of them were really hard, but because we worked SYSTEMATICALLY we could figure them all out. We used place values a lot and then guessed and checked.
We also practiced explaining your solutions. It isn't always enough to solve a problem - we often need to explain our solutions so that other people understand.