Inside, Outside And Across Bets
The INSIDE BET is that which involves the "inside numbers," which happen to be 5, 6, 8 and 9. The Inside Bet is a bet across all those numbers. As the player, you would start with a $5 Pass Line bet, then make a bet of $22 on the inside. You may be wondering how we came up with that. Well, you will be assigning a dollar value to each of these numbers, so you'll bet $6 on both the 6 and 8 (we do this because of the 7/6 payoff) and $5 each on the 5 and 9. That becomes a total of $12 + $10 = $22. if one of the aforementioned numbers is the point, you simply eliminate it from the equation and you'll be making an "inside bet" of either $16 or $17.
The OUTSIDE BET involves the "outside numbers," which are 4, 5, 9 and 10. Since there is no 6 or 8 in there, you will assign $5 to all four, making your bet $20, plus of course, the initial $5 Pass Line bet.
The ACROSS BET is a bet on every place number except for the point. For example, if 6 is the point, you will bet $6 on the 8 (because of the 7/6 payoff) and $5 each on the 4, 5, 9 and 10, making a total of $26. If 6 or 8 is NOT the point, then you bet $6 on both the 6 and the 8, $5 on three of the four other numbers. That's $12 + $15 = $27.
This method of combining Pass Line bets with these special bets is not an entirely unusual strategy. Sometimes this is combined with making Come bets, so that as numbers are rolled, you win the Place bet on that number and replace it with the Come bet, which would automatically be placed on that number.

