Sep 14
2008


For this piece of magic you need a pretty clever audiences who is good at taking away (or can use a calculator).
Ask them to work this sum out:
 Write down a three digit number where all the digits are different.
eg 317  Reverse the digits eg 713
 Take the smaller number from the larger number
713
317
 
396  Ask them to tell you the hundreds digit or the units digit and you will be able to tell them the whole answer without knowing what numbers they chose!
THE SECRET:
The answer always has a 9 in the tens column. The hundreds digit and units digit always adds up to 9.
So, if the clever spectators says the hundreds digit is 3 you can work out that the units must be 93=6.
So the number must be 396.
If the clever parent says the hundreds digit is 5 that means the units will be 95=4 and the whole number will be 594 etc etc
Try it out for yourself, but make sure your spectators gets the subtraction correct!
Comments (8)
Another way!
(ac)*100(ac).
So here for instance the number is 317 that means a=3, b=1 and c=7. So ac=4 and the result is
4*100(4)=396. Just remove the minus if you get something less than zero.
I find this easier to do. Try it yourself!
Another way!
(ac)*100(ac).
So here for instance the number is 317 that means a=3, b=1 and c=7. So ac=4 and the result is
4*100(4)=396. Just remove the minus if you get something less than zero.
I find this easier to do. Try it yourself!