The CAS Registry Mumber 17995-45-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,7,9,9 and 5 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 17995-45: (7*1)+(6*7)+(5*9)+(4*9)+(3*5)+(2*4)+(1*5)=158 158 % 10 = 8 So 17995-45-8 is a valid CAS Registry Number.