# Blog

## Brainteaser: Walkin’ the perimeter

By Ariel Marcy, 16 July 2024

Lavonne is a security guard who has to walk around the outside of an L-shaped building. She knows the length of the longest sides, 200 metres and 140 metres. She also knows the shape of the building and that each of the angles are 90 degrees. What is the building’s perimeter?

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## Brainteaser: Chessboard challenge

By Ariel Marcy, 4 July 2024

One day, Rumi’s chess club coach asks her, “how many squares are on a chess board?” Rumi replies, “That’s easy, the board is 8 by 8, so there are 64 squares!” Her coach smiles, “What about the larger squares made up of smaller squares? The board is an 8 by 8 square after all!” How many squares are on a chess board?

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## Brainteaser: Triangle plus

By Ariel Marcy, 18 June 2024

The teacher challenges Becki and her classmates to find three bottom numbers that follow the pattern and add up to 15. Becki is pretty sure that there are multiple solutions, where the numbers along the bottom appear in different orders. If she keeps at it, how many different solutions will Becki find?

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## Brainteaser: Sharing so much chocolate

By Ariel Marcy, 29 May 2024

Anamaria and Chen are two friends who toured a magical chocolate factory! They both get enormous amounts of chocolate and they want to share it evenly between them. Anamaria gets 1,574,936 squares of chocolate and Chen gets 3,569,321 squares of chocolate. Without using a calculator, can you tell if it is possible for them to share the chocolate between them without breaking any squares?

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## Brainteaser: Patchwork problem

By Ariel Marcy, 21 May 2024

Difficulty: Tricky Jack is making a quilt from only square patches of fabric. For every 4 patches he sews together, 1 patch is blue and 3 patches are red. Once they are added to the quilt, all of the patches are 5 cm in width and length. Jack wants to make a quilt that is […]

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## Brainteaser: Magic trick tricks

By Ariel Marcy, 24 April 2024

Miguel hopes to become a magnificent mathematical magician. For his first trick he wants to present a standard 52-card deck and dramatically draw a face card (Jack, Queen or King). If the deck is randomly shuffled, what is the probability that Miguel will draw a face card on the first try?

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## Massive multiplication

By David Shaw, 10 April 2024

Sienna’s teacher is writing up a wicked problem. First, the teacher writes all the numbers from 1 to 99 and then erases 10, 20, and all the other numbers that end in 0. “Listen up! Multiply all these numbers. Tell me the last digit and I’ll give you full marks on your next assignment.”

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## Brainteaser: Skipping stairs

By Ariel Marcy, 21 March 2024

Flora likes to run up stairs as fast as she can! Sometimes she lands on every stair and sometimes she skips a stair, taking two in one stride. This gets her thinking: how many different ways can she run up a staircase?

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## Secret pairs

By Ariel Marcy, 12 March 2024

Lavonne is testing a secret code with her friend Jack. First, she picks 3 different secret numbers between 1 and 9. Then she finds the sum of each pair of numbers. Lavonne wants to know if Jack can figure out the original secret numbers just from the sums?

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## Brainteaser: Egg-cellent farming

By Ariel Marcy, 26 February 2024

Farmer Wallace packages his eggs in cartons that hold a dozen eggs. In March, he sells 5 standard orders of eggs to the local grocery store. Each standard order consists of 4 grosses of eggs. A gross is 144 eggs. How many cartons of eggs did Farmer Wallace sell?

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