Number Challenge from Will Shortz and NPR

October 18, 2017 at 8:07 am 2 comments

Typically, the NPR Sunday Puzzle involves a word-based challenge, but this week’s challenge was a number puzzle.

[This challenge] comes from Zack Guido, who’s the author of the book Of Course! The Greatest Collection of Riddles & Brain Teasers for Expanding Your Mind. Write down the equation

65 – 43 = 21

You’ll notice that this is not correct. 65 minus 43 equals 22, not 21. The object is to move exactly two of the digits to create a correct equation. There is no trick in the puzzle’s wording. In the answer, the minus and equal signs do not move.

Seemed like an appropriate one to share with the MJ4MF audience. Enjoy!

Entry filed under: Uncategorized. Tags: , , , , .

The Homework Inequality: 1 Great Problem > 50 Repetitive Exercises Morelli, Coleman, and Statistical Outliers

2 Comments Add your own

  • 1. Roger  |  October 22, 2017 at 9:45 pm

    Thanks for the info. I’ve got an answer but won’t submit it, since I can’t be available in case they call on Thursday. 😉 Leave a comment if you’d like to compare notes…

    • 2. venneblock  |  October 24, 2017 at 7:49 am

      The NPR contest is open to the public until this Thursday. We should delay any discussion till after then. Thanks!


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About MJ4MF

The Math Jokes 4 Mathy Folks blog is an online extension to the book Math Jokes 4 Mathy Folks. The blog contains jokes submitted by readers, new jokes discovered by the author, details about speaking appearances and workshops, and other random bits of information that might be interesting to the strange folks who like math jokes.

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Math Jokes 4 Mathy Folks is available from Amazon, Borders, Barnes & Noble, NCTM, Robert D. Reed Publishers, and other purveyors of exceptional literature.

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