The CAS Registry Mumber 26328-69-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,6,3,2 and 8 respectively; the second part has 2 digits, 6 and 9 respectively. Calculate Digit Verification of CAS Registry Number 26328-69: (7*2)+(6*6)+(5*3)+(4*2)+(3*8)+(2*6)+(1*9)=118 118 % 10 = 8 So 26328-69-8 is a valid CAS Registry Number.