Tuesday, June 21, 2011

Math Teachers at Play #39

Check it out, over at Let's Play Math.

I like 39 because it's part of the first fraction that can be simplified, but isn't obvious ... 39/52.

Denise gave us these puzzles:
  • Easy: Can you make 39 with four 3s?
  • Tricky: Can you make 39 with four 4s?
  • Really tough: Can you make 39 with this year’s digits, keeping the numbers in order (2, 0, 1, 1)?

For the 'tricky' one, it may help to know that decimals are allowed (so you can use things like .4). I can't imagine how the 'really tough' one is possible.

Next month's Math Teachers at Play blog carnival, Number 40, will be here on July 15.


  1. Oops! In moving furniture this past week, I lost my Year Game notes. But I think the "really tough" puzzle of making 39 with 2,0,1,1 probably made use of a multifactorial or repeating decimal, or both...

  2. 39 written in base 19 is 21. So 20 + 1 * 1 = 21 works for me.

  3. Niice! (I guess I would have figured you had to write the base down.)


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