I am working up a color match effect where the participant will have the choice of five different colored markers and he will have the choice of five different items to color. He will color in all 5 different items with a different color.

What are the total possible combinations? I am thinking the odds are 1 in 120? My mind keeps thinking that is too low?

Rowdymagi5,
I think your thinking is correct. Five items to be colored with five colors. First item can be colored 5 ways; second item 4 ways; third item 3 ways; forth item 2 ways; fifth item is forced. 5x4x3x2x1 = 120 different colorings possible. I hope this helps.
leonard

Thanks!

Even though it goes against my sensibilities as someone with a University degree in Mathematics, I sometimes fudge the numbers when talking about probabilities to laymen to make the effect seem more impossible.

For instance, if you were to perform a Do As I Do routine, the odds of the two chosen cards matching is 1 in 52 because it can be any arbitrary card. That is, the first card chosen can be anything at all. However, before the reveal when presenting this effect I would say something along the lines of "The odds of you choosing your particular card is 1 in 52. The odds of me choosing a particular card is also 1 in 52. So the odds of you choosing that Ace of Diamonds and then me ALSO choosing the Ace of Diamonds is 1 in 52 TIMES 52... or less than 1 in 2500!"

Most people aren't terribly good at math, never mind calculating probabilities. The above explanation sounds completely sensible. In fact it is, it just doesn't describe that particular situation accurately. Nobody knows that though and so they accept the number and the feat goes from a mere "1 in 52 chance" to "1 in over 2000". Much better.

In the case of colour match, you could spin it in a similar way. Rather than leave it as 1 in 5, then 1 in 4, etc... you could simply say there was a 1 in 5 chance for each colour. That makes the odds 1 in 5^5 or 5x5x5x5x5 = 3125. You could go really off the wall and say that with each selection, they could have chosen any of the 5 colours and you could have chosen and of the 5 items to colour. So the odds of a match were 1 in 25. Repeated 5 times, the odds of this experiment being a perfect match would be 25^5. Ask someone to punch that into their calculator and they get 1 in 976,000! As is often that case in magic and mentalism, you go with what you think you can get away with!

Cheers,
Rob VH