If you have more than 2 sets of Straight 4D numbers, you can go for System Play. It allows you to cover all combinations of 4D Straight bets from a minimum of 3 sets of 4D numbers, up to a maximum of 20 sets.
If you bet on 3 sets of 4D numbers, you will be playing System 3 (This concept applies from System 3 to System 20).
i-System
If you have more than 10 sets of Straight 4D numbers, you can go for i-System. It allows you to cover all combinations of 4D Straight bets from a minimum of 10 sets of 4D numbers, up to a maximum of 20 sets.
If you bet on 10 sets of 4D numbers, you will be playing i-System 10 (This concept applies from i-System 10 to i-System 480).