The CAS Registry Mumber 64695-86-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,4,6,9 and 5 respectively; the second part has 2 digits, 8 and 6 respectively. Calculate Digit Verification of CAS Registry Number 64695-86: (7*6)+(6*4)+(5*6)+(4*9)+(3*5)+(2*8)+(1*6)=169 169 % 10 = 9 So 64695-86-9 is a valid CAS Registry Number.