See the MM author KJARTAN POSKITT do a few tricks including The Fabulous Flexagons, The 71113 Trick and The Mysterious Extra Square 
Some of these tricks are in the Murderous Maths books, but here I can let you play on my special calculators and other computer gadgets!

For everything from games to puzzles, from books to DVDs, and from coffee pots to bits of wire with funny plugs on the end, and even radio controlled Daleks visit THE MURDEROUS MATHS SHOP 
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The EIGHT QUEENS Puzzle!
A classic Sam Loyd Problem.
The 71113 Trick (And other miracle sums)
Pass your friends a calculator  and then
make them feel really silly with these simple tricks!
The Predictor Cards The trick with four cutout cards, you pick a number from 116 and it mysteriously appears in a hole at the back!
The Missing Digit Trick
Your friend does a sum then crosses a digit out  you can tell what it is without looking!
The Prime Numbers Trick
Make a strange prediciton using the magic of
PRIME NUMBERS. There's even a special calculator to
play with!
The Five Card Trick
A sneaky little trick you can carry round in
your pocket. Very easy to make and perform!
The Calendar Trick
You see calendars everywhere  so next time
why not utterly gobsmack your friends with a
lightning mental calculation?
Urgum and Grizelda's Head Hunt
A skill game to play on your own or with 1 or 2 fellow
barbarians.
What were you like when you were born?
Use your date of birth to discover your true character!
http://www.cleaningservicenewyorkcity.com/  Need time to figure out these games &
tricks
?
Hire a cleaning service for your NYC
office
so you can get get working on these tricks and games.
The Impossible Guess!
So you think you're clever eh?
In that case I challenge you to guess my secret number...
The Impossible Drawing Trick
Challenge your friends to this neat little trick  it'll drive
them mad especially when you show them the answer!
The Fabulous Flexagons
How to make two of the strangest toys you ever saw!
The MODULUS 105 trick
An amazing way of finding a number using the special maths MOD function.
Age By Chocolate!
A great trick that a lot of people know, but very few people understand!
Have you read the
first six books?
Then try
The Murderous Quiz!
SORRY! Some of the following games only work if your computer has JAVASCRIPT (whatever that is).
Yahtzee!
Learn to play the famous dice game then challenge a friend!
Dolly's Rush Hour!
Use your logic skills to help Dolly escape the car park!
Riverboat Lil's Chase The Kings Game!
See if you can work out the sequences needed to clear a whole pack of cards!
3D Noughts and Crosses
Whether you call it "Noughts and Crosses" or "Tic Tac Toe"  can you beat the computer in three dimensions at once?
Pongo Mc Whiffy's Pants Race.
Pongo (from the Murderous Maths books) invites you to place your bets!
And here is one of the strangest toys on the whole of maths
The Sam Loyd Puzzle
The classic sliding tiles problem to
play right here on your screen!
The Apple Scoffing Game
A neat little puzzle which you'll NEVER beat me at!
If I find any other good stuff, I'll put it here for you.... so make sure you come back and see me again!
Links:
sent their OWN Brainbenders!
TRY THESE  THEY'RE TOUGH!