by David, 30 September 2020 | 0 comments

Difficulty: Taxing Grab a calculator (or a pen and paper) Choose a three-digit number (e.g. 123) Multiply it by 7 Multiply the answer by 11 Multiply that answer by 13 You will get your starting number written out twice! (e.g. 123 123) The question is, can you work out why?

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by David, 17 September 2020 | 0 comments

Around 3500 years ago, the Minoan people lived on the island of Crete. They had a written language, now known as Linear A, which archaeologists cannot decipher. They also had an advanced number system, which experts are finally beginning to crack!

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by David, 16 September 2020 | 1 comments

Difficulty: Tricky We’re going to make a magic triangle! Take the numbers 1–6 and arrange them in a triangle with three numbers on each side. Swap them around until the sides all add up to the same number.

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by David, 27 August 2020 | 1 comments

By Mike McRae Double Helix magazine is looking for your questions! Our Microscope column answers the most intriguing science, tech, engineering and maths queries you can throw at us.

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by David, 26 August 2020 | 1 comments

Difficulty: Taxing Here’s a beautiful artwork from 1895, titled Mental calculation. In public school of S. A. Rachinsky, painted by Nikolay Bogdanov-Belsky. Can you solve the puzzle the kids are pondering? If you can’t quite see the equation, here it is:

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by David, 20 August 2020 | 0 comments

Craft yourself a mathematical ring to learn about straight lines on donuts. Don’t laugh, they do exist!

Continue reading Geodesic ringsby David, 19 August 2020 | 0 comments

Difficulty: Tricky Gertrude has a collection of shapes that she likes to arrange in patterns. She starts with a regular hexagon with 10 cm sides, and three regular triangles that also have 10 cm sides. She arranges the triangles around the hexagon, and then lines them up. In the end, one side of each triangle…

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by David, 3 August 2020 | 4 comments

Difficulty: Fun I’m thinking of three numbers. They are consecutive counting numbers. When you add the first two numbers together, you get the third number. What numbers am I thinking of?

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by David, 22 July 2020 | 1 comments

Difficulty: Tricky Ari was 10 on her last birthday, and will be 12 on her next birthday. How can this be true? Lachlan was 8 on his last birthday, and will be 12 on his next birthday. How can this be true?

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by David, 21 July 2020 | 2 comments

Right now, there are about 7.8 billion people on Earth, and that number keeps on growing. But could this growth be coming to an end? Experts have made a new prediction that Earth’s population will not reach 10 billion people. And the reasons why are surprisingly positive.

Continue reading How many people will there be in 2100?Categories: