The CAS Registry Mumber 3614-16-2 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 3,6,1 and 4 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 3614-16: (6*3)+(5*6)+(4*1)+(3*4)+(2*1)+(1*6)=72 72 % 10 = 2 So 3614-16-2 is a valid CAS Registry Number.