The CAS Registry Mumber 1622-00-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,6,2 and 2 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 1622-00: (6*1)+(5*6)+(4*2)+(3*2)+(2*0)+(1*0)=50 50 % 10 = 0 So 1622-00-0 is a valid CAS Registry Number.