Most likely...most of these chips come from either the poker tables, or the craps table. These are just my thoughts about the topic...me just knowing craps odds like I know my own address.

If you take free odds on a $5 bet on 5 or 9, the payout is 3 to 2. (Which works out as $7.50 to $5.) Most casinos will only pay out 7 to 5 which means that the $.50 is a pretty large vigorish taken by the casino. (If you are betting $500, then that's $50 the casino is taking from you...it adds up quick.)

Then...I have been reading that more and more poker rooms are using all chips in even and odd amounts. Many places are starting $1-2, 2-4, 3-6, 4-8, 5-10, 6-12, 7-14, all the way up to 9-18 games for those people who really don't know how to play poker.

The casino philosophy is about higher vigorish percentages on the rake. Go figure...

That's just my thoughts on the odd denominations...