The CAS Registry Mumber 6615-95-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 6,6,1 and 5 respectively; the second part has 2 digits, 9 and 5 respectively. Calculate Digit Verification of CAS Registry Number 6615-95: (6*6)+(5*6)+(4*1)+(3*5)+(2*9)+(1*5)=108 108 % 10 = 8 So 6615-95-8 is a valid CAS Registry Number.