Stage: 2 Challenge Level: 
Here is a grid which looks a little like spots on dice or dominoes:
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Full Screen Version
Can you see why 2 by 2 is 5?
What is 2 by 3? You may like to use the interactivity above to explore.
2 by 4?
2 by 5?
Can you predict what 2 by 10 will be? Explain how you know.
What is 3 by 2?
3 by 3?
3 by 4?
Predict what 3 by 10 will be and explain how you arrived at your solution.
How about 10 by 2?
10 by 3?
10 by 10?
2 by 4?
2 by 5?
Can you predict what 2 by 10 will be? Explain how you know.
What is 3 by 2?
3 by 3?
3 by 4?
Predict what 3 by 10 will be and explain how you arrived at your solution.
How about 10 by 2?
10 by 3?
10 by 10?
Addition & subtraction. Visualising. Practical Activity. Compound transformations. Trial and improvement. Working systematically. Games. Multiplication & division. Interactivities. Generalising.
Published May 2005.
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email: nrich@damtp.cam.ac.uk