The CAS Registry Mumber 30101-03-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,0,1,0 and 1 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 30101-03: (7*3)+(6*0)+(5*1)+(4*0)+(3*1)+(2*0)+(1*3)=32 32 % 10 = 2 So 30101-03-2 is a valid CAS Registry Number.