Criss-Cross Numbers

Task 39 ... Years 2 - 7

Summary

This is a hands-on 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.

Materials

Counters numbered as shown in the photo
Puzzle board

Content

place value
if-then reasoning
creating and solving equations

Iceberg

A task is the tip of a learning iceberg. There is always more to a task than is recorded on the card.

Where would you start and why?
...There is only one three digit number with a 3 in the tens column, so 438 is a good choice for the first column.
One solution is...
...Are there others?
When you have a solution, number your puzzle boxes in the same way as a crossword is numbered. Create equations ('sums') which have the puzzle answers as their answers. Try your equations out on another student.
Create your own Criss-Cross Number puzzle. Is it possible to create one with no printed clues on the puzzle, and have a unique solution?
Create your own Criss-Cross Number puzzle where the clues are equations.

Whole Class Investigation

Tasks 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.

Is it in Maths With Attitude?
Maths With Attitude is a set of hands-on learning kits available from Years 3-10 which structure the use of tasks and whole class investigations into a week by week planner.
The Criss-Cross Number task is an integral part of:

MWA Number & Computation Years 3 & 4

This task is also included in the Task Centre Kit for Aboriginal Students.

Follow this link to Task Centre Home page.