The CAS Registry Mumber 80616-62-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,0,6,1 and 6 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 80616-62: (7*8)+(6*0)+(5*6)+(4*1)+(3*6)+(2*6)+(1*2)=122 122 % 10 = 2 So 80616-62-2 is a valid CAS Registry Number.