The CAS Registry Mumber 21206-60-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,1,2,0 and 6 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 21206-60: (7*2)+(6*1)+(5*2)+(4*0)+(3*6)+(2*6)+(1*0)=60 60 % 10 = 0 So 21206-60-0 is a valid CAS Registry Number.