The CAS Registry Mumber 793668-08-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 7,9,3,6,6 and 8 respectively; the second part has 2 digits, 0 and 8 respectively. Calculate Digit Verification of CAS Registry Number 793668-08: (8*7)+(7*9)+(6*3)+(5*6)+(4*6)+(3*8)+(2*0)+(1*8)=223 223 % 10 = 3 So 793668-08-3 is a valid CAS Registry Number.