Triple Nine Wall Clock - a Timely Student Math Challenge for Clockwatchers

Here’s a neat challenge for your students: Ask them to find a way to represent each of the positive integers from 1 through 12 using exactly three 9’s.

This puzzle is a variation of the Four 4’s puzzle: Write each of the positive integers using exactly four 4’s. Some sample answers include the following.

1 = (4+4)/(4+4)

2 = 4/4 + 4/4

3 = (4+4+4)/4

This clock can actually be found online for purchase at cafepress.

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Tags: cafepress, Math Activity, math challenge, numerical reasoning, Problem-Solving, Puzzle