Weights, Crazy Geometry Game, and Pumpkin Polyhedra

Welcome to this week’s Math Munch!

Weighing puzzleHere’s a puzzle for you: You have 12 weights, 11 of which weigh the same amount and 1 of which is different. Luckily you also have a balance, but you’re only allowed to use it three times. Can you figure out which weight is the different weight?

You certainly can! I won’t tell you how, but you can figure it out for yourself while playing this interactive weight game. This puzzle is tricky, but definitely fun. If one weight puzzle isn’t enough for you, you’re in luck– there are many, many variations! Check out this site to try a similar puzzle with nine weights, ten weights, and 27 weights.

Circle two pack

My solution to the Circle Pack 2 challenge. Can you do it in only 5 moves?

Next up, if you like drawing challenges, this is the game for you. Check out this crazy geometry game, in which you have to draw different shapes (like perfect equilateral triangles, squares, pentagons, and groups of circles of particular sizes) using only circles and straight lines! Here’s my solution to one of the challenges, the Circle Pack 2. See the two smaller circles inside of the larger middle circle? That’s what I wanted to draw– but I had to make all of those other circles and lines to get there! I did the Circle Pack 2 challenge in 8 moves, but apparently there’s a way to do it in only 5…

Truncated icosahedron pumpkinFinally, it’s pumpkin season again! Every year I scour the internet for new math-y ways to carve pumpkins. We’re all in luck this year– because I found great instructions for how to carve pumpkin polyhedra from Math Craft!  Check out this site to learn how to carve all the basics– tetrahedra, cubes, octahedra, dodecahedra, and (my favorite) icosahedra– and a bonus polyhedron, the truncated icosahedron (also know as the soccer ball).

Pumpkin polyhedra

Pumpkin Platonic polyhedra!


Don’t forget to make pi with the leftover pumpkin! Oh, and, bon appetit!



20 responses »

    • Hi, Andres! Thanks for your comment. Would you like more numbers on the weights puzzle or the geometry game? Or both? I think it would be really interesting to try to make up new levels for each game. I wonder if adding more weights/numbers always makes the weights puzzle more difficult, or if sometimes adding weights (and weighings) might make it easier…

  1. Wow this is hard but i kept tying and trying at first i did not understand it but I saw it carefully and I solved it my question is was it hard for you to solve this and the pumpkin one looks kind of hard but I hope I could do it with my family

  2. Pingback: Scary-o-graphic Projection, Thinky the Dragon, and Martin Gardner | Math Munch

  3. this is very hard but maybe if you added a little less numbers it would be easier but i honestly like it hard so if you added more numbers it would be harder

  4. This is so cool ! I wonder how someone came up with the idea to do this. Sadly I didnt get the video I thinkit should have been more involved with math instead of it trying to be a horror video.

  5. Pingback: George Washington, Tessellation Kit, and Langton’s Ant | Math Munch

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