# Blog

## Red and black brainteaser

By David Shaw, 12 June 2019

I have four playing cards: two of them are black and two are red. I turn them face down so you can’t see the colours, and shuffle them so you don’t know which is which.

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## Taping tarps brainteaser

By David Shaw, 29 May 2019

Gerri has two identical square tarpaulins. Unfortunately, these tarps aren’t quite big enough to cover the brand new spa bath. So Gerri’s decided to cut the tarps and tape them together to make a bigger tarp. They want their final tarp to be a square, and they want it to be as big as possible.

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## Sibling survey

By David Shaw, 15 May 2019

Emily has twice as many brothers as she has sisters. Her brother Bill has one more sister than he has brothers. How many boys and girls are in Emily and Bill’s family?

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## The triple bounce

By David Shaw, 1 May 2019

I’m thinking of a two digit number. If you add the digits together and then multiply by three, you get the number back again! What number am I thinking of?

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## The big triangle brainteaser

By David Shaw, 17 April 2019

At Three Peaks School, they’re planning to build a gigantic triangle. The sides have just arrived, on the back of some truly ridiculous trucks, and with police escort.

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## Blue eyed cows brainteaser

By David Shaw, 3 April 2019

Imagine a place called Occhiblu station, where they’re trying to breed cows with blue eyes. They have 100 cows on the station, and some of them have one blue eye. Of the rest of the cows, half have two blue eyes.

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## Checking the clock brainteaser

By David Shaw, 20 March 2019

Terry is inspecting a huge clock. It’s 2:12 and they just finished examining the big hand.

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## Mathematical pizza party

By David Shaw, 6 March 2019

Four mathematicians – Annie, Beth, Carol and Donna – have a fun tradition. Every Friday, they order a pizza. But before they can eat, they must each solve a puzzle.

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## No zeros

By David Shaw, 20 February 2019

Which two whole numbers – without any zeros – multiply together to make 1 000 000?

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