The CAS Registry Mumber 76765-85-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,7,6 and 5 respectively; the second part has 2 digits, 8 and 5 respectively. Calculate Digit Verification of CAS Registry Number 76765-85: (7*7)+(6*6)+(5*7)+(4*6)+(3*5)+(2*8)+(1*5)=180 180 % 10 = 0 So 76765-85-0 is a valid CAS Registry Number.