The CAS Registry Mumber 18530-50-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,8,5,3 and 0 respectively; the second part has 2 digits, 5 and 0 respectively. Calculate Digit Verification of CAS Registry Number 18530-50: (7*1)+(6*8)+(5*5)+(4*3)+(3*0)+(2*5)+(1*0)=102 102 % 10 = 2 So 18530-50-2 is a valid CAS Registry Number.