The CAS Registry Mumber 53317-10-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,3,3,1 and 7 respectively; the second part has 2 digits, 1 and 0 respectively. Calculate Digit Verification of CAS Registry Number 53317-10: (7*5)+(6*3)+(5*3)+(4*1)+(3*7)+(2*1)+(1*0)=95 95 % 10 = 5 So 53317-10-5 is a valid CAS Registry Number.