User:Test7206310/isbn

Adding 2 to 130 gives a multiple of 11 (because 132 = 12×11) – this is the only number between 0 and 10 which does so. Therefore, the check digit has to be 2, and the complete sequence is ISBN 0-545-01022-5. If the value of $$x_{10}$$ required to satisfy this condition is 10, then an 'X' should be used.