The CAS Registry Mumber 1173110-39-8 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,1,7,3,1,1 and 0 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 1173110-39: (9*1)+(8*1)+(7*7)+(6*3)+(5*1)+(4*1)+(3*0)+(2*3)+(1*9)=108 108 % 10 = 8 So 1173110-39-8 is a valid CAS Registry Number.