Cumulative Random Match Probability is the product of multiplying the probability for each marker that the number resulted from chance. For instance, the chance to receive scores of 10 and 11 at one marker location is .16: 16% of the population have 10 and 11 at that marker. Moving on to the next marker, the chance for a random match may be 4%. To get the cumulative RMP, you multiply all the percentages together. Taking them all into account whittles the overall chance for a random person to have the same genotype to 1 in 7000, or 1 in a million, or 1 in a quadrillion, usually a very slight, remote possibility.
The probability of a particular multi-locus genotype is obtained by multiplication — by multiplying together the frequencies of the per-locus genetypes, which is to say, by multiplying together the frequencies of all the individual alleles to obtain the frequency of a particular DNA profile, or fingerprint. The higher the RMP, the rarer your DNA.
RMP can be inverted and it then becomes match likelihood. For example, you may be three times more likely to match people from Finland than anyone else.