Monday, January 18, 2016

Ana and son explain another cool math puzzle


Remember the card trick on YouTube, where the poster begged someone to explain how it worked? Ana and her son Julio figured it out and the explanation is here, in Ana's own handwriting.

Now they've done another one. She and her son loved a puzzle Will Shortz used on his regular feature on a recent Weekend Sunday, on NPR. It's simple (but not that easy). Here's the puzzle: 

Using only standard mathematical symbols (x, ., /, ÷,  etc.) make three nines (9, 9, and 9) equal 20. 

Ana was embarrassed that Julio figured it out before she did, but it might be because Julio grew up knowing Earth's standard mathematical notation system. Ana didn't. She came to it as an adult, when she arrived on the moon from Thomo. Thoman math uses different symbols. Our symbols are a second language to her, mathematically speaking. 

When you give up, you may find the answer, plus Julio's insightful understanding of this problem, here.

(The wildflowers--wine cups--are only a reminder of warmer weather.)

Other puzzles from our extraterrestrial Distant Cousin:




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