Reduction systems allow you to play more doubles and triples than normal. These systems are composed of prognosis singles matches, doubles and triplesin the form of several simple grids (double or triple without) - it happens,however, that some systems generate grids containing some double or triple. System 7 in 8 double grids guarantees 13 (a Lotofoot 15) was played on 8 simple grids.
7 double play normally and normally requires 2x2x2x2x2x2x2 = 128 grids Simple. Now the system 7 in 8 double gates guarantees 13 (a Lotofoot 15) takes only 8 simple grids. In return there is no guarantee a result to 13. This means that having the entire fair prognosis (7 doubles and all just fixed),there will be a minimum of 8 grids which will have 13 results.