The CAS Registry Mumber 773786-93-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 7,7,3,7,8 and 6 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 773786-93: (8*7)+(7*7)+(6*3)+(5*7)+(4*8)+(3*6)+(2*9)+(1*3)=229 229 % 10 = 9 So 773786-93-9 is a valid CAS Registry Number.