CrissCross NumbersTask 39 ... Years 2  7SummaryThis is a handson example of Cross Number (cf: Crossword) puzzle. Using the numbered counters makes it easier (and safer?) than a pencil and paper version. The problem is to fill the empty spaces knowing only the numbers in the completed puzzle and a few given digits.The puzzle is equivalent to completing a crossword with no clues other than the words in the puzzle, a few correctly placed letters and sufficient scrabble tiles to complete all the words. 
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IcebergA task is the tip of a learning iceberg. There is always more to a task than is recorded on the card. 
Reasoning is the focus of this task. Encourage students to notice and record their reasoning at each step. The first step is (should be?)...
One solution is... ...Are there others? Extensions

Whole Class InvestigationTasks are an invitation for two students to work like a mathematician. Tasks can also be modified to become whole class investigations which model how a mathematician works. 
Use the photograph as a guide to making your own printed version of the task in a program like Word. Create the equivalent of the number tiles as a printed sheet which pairs of students cut into the nineteen tiles required. Use the activity to highlight and share the strategies students use to complete the puzzle. Extend the puzzle with challenges such as those above. Consider encouraging the students to make a class set of puzzles. Those which pass agreed criteria could then be published in a more permanent form. At this stage CrissCross Numbers does not have a matching lesson on Maths300. 
Is it in Maths With Attitude?Maths With Attitude is a set of handson learning kits available from Years 310 which structure the use of tasks and whole class investigations into a week by week planner. 
The CrissCross Number task is an integral part of:
