The CAS Registry Mumber 13264-03-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,3,2,6 and 4 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 13264-03: (7*1)+(6*3)+(5*2)+(4*6)+(3*4)+(2*0)+(1*3)=74 74 % 10 = 4 So 13264-03-4 is a valid CAS Registry Number.