The CAS Registry Mumber 23449-95-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,3,4,4 and 9 respectively; the second part has 2 digits, 9 and 5 respectively. Calculate Digit Verification of CAS Registry Number 23449-95: (7*2)+(6*3)+(5*4)+(4*4)+(3*9)+(2*9)+(1*5)=118 118 % 10 = 8 So 23449-95-8 is a valid CAS Registry Number.