This week we solved a tricky puzzle involving swords and trying to sit in the right position of a circle to survive!
This applet on Geogebra can be used to explore the problem.
A powerpoint, created at the Ghana Maths Camp in 2015, explaining the puzzle and with solution is here.
The puzzle that we solved this week can be solved by hand, but excel is a very useful tool!
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23.
Find the sum of all the multiples of 3 or 5 below 1000.
This puzzle was taken from Project Euler Website, where there are lots more puzzles to try, all designed to be solved with a computer.
See if you can be the magician …
Deal three piles of three cards. Ask someone to choose a pile and look at the bottom card without showing you the card. Put the three piles together, with the chosen pile on top.
Then count off cards while spelling some words such as “Thomas is clever”. The first word should have at least three letters and a maximum of nine letters, the second word should have two letters, and the third word should have at least five letters and a maximum of nine letters.
For each word, deal the top cards in the deck onto a separate pile, and then put the dealt cards back under the bottom of the deck before proceeding to the next word.
Finally, spell out the word ‘MAGIC’; the chosen card will be the card at ‘C’ – so you can flip this card over and amaze your audience!
This trick also works if you look at the card that is chosen at the start, and then spell it out e.g. TWO OF SPADES MAGIC.
Why does it always work?