Mathematics can become magical: amazing tricks with numbers, so easy for everyone to attend though so difficult to reveal the well-hidden mathematical ideas. This was the subject of Prof. Michalis Lambrou’s talk on the 6th of the December 2017, when he was invited by the “MathMagic Club” of our school, coordinated by the mathematician Mr. Alexandros Sygkelakis. Prof. M. Lambrou, being himself an excellent educator, not only as a Professor in the Mathematics Department at the University of Crete, but also as a trainer to teachers and students, gave thrust to our imagination and expanded our capacity of understanding and before he revealed each mathematical idea he had made us think about it. We all thank him for this wonderful trip to the mathematical magic!

The talk was recorded by Mr. Antonis Margaritis, teacher of Chemistry in our School. We warmly thank him!

In the end of this article, there are two interactive mathematical tricks, of those Prof. Μ. Lambrou presented and explained in his talk.

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1. The magic sum

Choose a number from the table below and click on it. Then all other numbers in the same row and column will be deleted. Choose another one from the remaining numbers and click on that too. Continue thus. In the end you will have exactly 4 numbers, one in each row and column. Is their sum equal to 39?

2. Transparencies with guessing abilities

Think of a number from 1 to 20. Some of the first six (out of seven) transparencies below include your number. For each one of these, click the button "Move" on the left, so that the transparency moves on top of the 7th one. Is it now clear which one is the number you've thought of?

Move

Move

Move

Move

Move

Move

Reset