This method is sometimes also known as the 'Cancellation System'. You begin with any series of numbers the series chosen will tally up to the number of units that you are trying to win in each sequence.

You begin by betting the sum of the first and last number in the series. If you win, cross out both of these numbers, if you lose, add the last bet made to the end of the series. Let's say, for example that the series used is 1-2-3-4-5-6. If you are successful in canceling out the entire sequence, you will win exactly 21 units, or 1 +2 +3 +4 +5 +6.

To illustrate, here is a sequence that we will play out (the "x" denotes numbers that are cancelled out after a winning bet): commencing sequence = 1-2-3-4-5-6+0 units.

1. bet 1 +6, or 7 units and win: x-2-3-4-5-x +7 units
2. bet 2 +5, or 7 units and lose: x-2-3-4-5-x-7 +0 units
3. bet 2 +7, or 9 units and lose: x-2-3-4-5-x-7-9 -9 units
4. bet 2 +9, or 11 units and win: x-x-3-4-5-x-7-x +2 units
5. bet 3 +7, or 10 units and win: x-x-x-4-5-x-x-x +12 units
6. bet 4 +5, or 9 units and lose: x-x-x-4-5-x-x-x-9 +3 units
7. bet 4 +9, or 13 units and win: x-x-x-x-5-x-x-x-x +16 units
8. bet 5 units and win: x-x-x-x-x-x-x-x-x +21 units

A longer series of larger numbers has less likelihood of success thus, the shorter the series and smaller the values, the better the chance of completing the series.