The CAS Registry Mumber 9079-77-0 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 9,0,7 and 9 respectively; the second part has 2 digits, 7 and 7 respectively. Calculate Digit Verification of CAS Registry Number 9079-77: (6*9)+(5*0)+(4*7)+(3*9)+(2*7)+(1*7)=130 130 % 10 = 0 So 9079-77-0 is a valid CAS Registry Number.