Mathematicians in Room 123 used what they know about tens and ones to place number cards on a grid. Then they had to explain why they placed the card where they did. When every student had a turn, I posed a question.
Of course, simply counting the empty squares would be too easy. Instead, students worked in problem-solving teams to solve this question. They realized that they had to add the cards I had placed and the cards they had placed. Then, they had to determine how many blank squares were left.
The teams used different strategies and math tools to solve the problem.
Then, they gathered to discuss their solutions!