How to Get a Bigger Brownie

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.

How to Get a Bigger Brownie

November 6, 2017

Normally you cut a tray of brownies with straight lines to make squares or rectangles. If the pieces come out uneven, you hope you get the biggest one. But this cool cake-cutter by Matthias Wandel makes hexagons instead! Check out those cool chocolate-chip bars. There are only 3 shapes with all equal sides and angles that can fit together with no gaps or overlaps: hexagons, squares…and can you think of the last one? Triangles. Try cutting your brownies that way, too!

Wee ones: How many sides does a hexagon have? Check out the picture!

Little kids: If you eat a hexagon brownie and then a normal square one, how many edges do they have all together?  Bonus: If you cut 2 straight lines across a square cake and then 2 straight lines from back to front, how many pieces will you have?

Big kids: If you cut your brownies into 6 rows of 4 hexagons plus 6 half-hexagons, how many total hexagons do you have?  Bonus: If you can fit 36 squares instead, how many more brownies do you have by cutting squares?

The sky’s the limit: By what fraction is each of 27 hexagons bigger than one of the 36 squares from the same size tray?




Wee ones: 6 sides.

Little kids: 10 edges, since the square has 4.  Bonus: 9 pieces — imagine a tic tac toe board.

Big kids: 27 hexagons, since the 6 halves give you 3 more.  Bonus: 9 more brownies.

The sky’s the limit: 1/3 bigger than a square. Each hexagon is 4/3 of a brownie, since you can cut only 3/4 as many of them. If you carve out 3/3 for the square brownie, you’re left with 1/3 extra.

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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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