What is wheeling system ?

In the game of Lotto you are asked to guess a certain quantity of numbers (for example 6) on a range of numbers varying from 35 to 90. For example in the Swiss Lotto you have to guess 6 numbers over a range of 45. This type of game is called a 6/45.
By guessing 6 numbers you obtain a first-class win, nevertheless you can also win by guessing a lower quantity of numbers. In some Lotto games you can win by guessing only 3 numbers.
Games with 6 numbers are called pick 6, with 5 numbers pick 5, etc.
In the pick 6 games each bet consists of 6 numbers (combination of 6 numbers). If you want to play more than 6 numbers a wheeling system is necessary. Let's say you want to play 8 numbers in order to obtain a first-class win if the 6 winning numbers are included in the range of the 8 numbers of your wheeling system.
To play such a system it is necessary to play all possible combinations of 6 numbers resulting from our 8 starting numbers. Just suppose you want to play the numbers from 1 to 8 there will be the following 28 bets (combinations or lines) : 

1 2 3 4 5 6
1 2 3 4 5 7
1 2 3 4 5 8
1 2 3 4 6 7
1 2 3 4 6 8
1 2 3 4 7 8
1 2 3 5 6 7
1 2 3 5 6 8
1 2 3 5 7 8
1 2 3 6 7 8
1 2 4 5 6 7
1 2 4 5 6 8
1 2 4 5 7 8
1 2 4 6 7 8
1 2 5 6 7 8
1 3 4 5 6 7
1 3 4 5 6 8
1 3 4 5 7 8
1 3 4 6 7 8
1 3 5 6 7 8
1 4 5 6 7 8
2 3 4 5 6 7
2 3 4 5 6 8
2 3 4 5 7 8
2 3 4 6 7 8
2 3 5 6 7 8
2 4 5 6 7 8
3 4 5 6 7 8

If the 6 winning numbers are all included among the 8 of our system, one of the a.m. 28 combinations will certainly contain the 6 winning numbers. Similarly, if only 5 of the 6 winning numbers are among the 8 of our system, the result will be that at least one of the 28 combinations will include the 5 winning numbers. The same if the winning numbers are 4, 3 or 2. Such system is called a full wheeling system.

If we increase the quantity of numbers in our system, the combinations to play will also increase very rapidly as you can deduce from the following scheme.

System Numbers        Number of bets (Combinations)

              7                                 7
              8                                28
              9                                84
            10                               210
            11                               462
            12                               924

As you can see, if the quantity of numbers increases, there will also be an enormous increase of the bets and consequently of the cost for our system.
In order to reduce this cost another type of wheeling system, the so called abbreviated wheeling system is used. This system only gives precise guarantees in certain cases. For example we can create some systems which can grant the win of the "4" if in our system there are exactly 4 winning numbers. Yet, we will not have a "5" win if we guess 5 numbers. Another type of system could assure the win of "5" with 6 winning numbers or the win of "4" with 6 winning numbers.
As you can see all these systems guarantee a precise win only if there is a certain quantity of winning numbers, however, they have the advantage of being much cheaper.
For example, a system of 10 numbers which guarantees a "4" win with 4 winning numbers consists of 20 combinations, while a full wheeling system would need 210!
All previous examples always refere to a pick 6 game, the process being the same for pick 5 or pick 7.