Back to Square One

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Back to Square One

January 23, 2013

One of the most popular and widespread toys ever invented is the Rubik’s Cube.  The mission is so simple: just turn the rows and columns to swap around the pieces and get all six faces to be solid colors.   And yet that turns out to be one of the hardest challenges out there – maybe because a 3x3x3 cube has over 43 quintillion possible line-ups of the pieces.  Ever since the cube was invented in 1974, over 350 million of these puzzles have been sold; the Cube has inspired people to set all kinds of records, spawning speed cubers, one-handed cubers, and the real geniuses who study the cube, blindfold themselves and solve it from memory.  To get a taste of the excitement, let’s look at the math behind cracking the code.

Wee ones: If each face of the cube is 3 squares across and 3 squares down, how many colored squares does each face have?

Little kids: If you need to make 9 more twists to get the corners in place and 8 more twists to line up the edges, how many moves away are you from solving the cube?  Bonus: If there are 9 squares on each face, how many squares does the whole cube have?

Big kids: Some people can solve the cube blindfolded after memorizing its scrambled pattern.  If the record for this solving is 26 seconds, and you need 5 times as long to solve it not blindfolded, how fast can you solve the cube?  Bonus: In the group-cubing record, 134 people all solved their cubes at the same time within 12 minutes.  If they averaged 11 minutes per cuber, how many total minutes of cube-twisting did they do?

 

 

 

Answers:
Wee ones: 9 squares.

Little kids: 17 moves.  Bonus: 54 squares.

Big kids: 130 seconds.  Bonus: 1474 minutes – just over 24 hours.

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About the Author

Laura Overdeck

Laura Overdeck

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.

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