The CAS Registry Mumber 53102-12-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,3,1,0 and 2 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 53102-12: (7*5)+(6*3)+(5*1)+(4*0)+(3*2)+(2*1)+(1*2)=68 68 % 10 = 8 So 53102-12-8 is a valid CAS Registry Number.