Need help understanding what this is...

[crmsontide14]

I am trying to place a bet online. What does it mean when a guy tells me to put in a $1 Trifecta like this:

4, 10/4, 9, 10/1, etc, etc

I can't get the slashes to come up and am a rookie at horse betting. Can someone help?

 

[Stang]

He wants 4 or 10 to win
4,9,10 for second place(place)
1 for third place(show)

Its called Key betting