The CAS Registry Mumber 3219-92-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 3,2,1 and 9 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 3219-92: (6*3)+(5*2)+(4*1)+(3*9)+(2*9)+(1*2)=79 79 % 10 = 9 So 3219-92-9 is a valid CAS Registry Number.