The CAS Registry Mumber 13411-64-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,3,4,1 and 1 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 13411-64: (7*1)+(6*3)+(5*4)+(4*1)+(3*1)+(2*6)+(1*4)=68 68 % 10 = 8 So 13411-64-8 is a valid CAS Registry Number.