The CAS Registry Mumber 75194-99-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,1,9 and 4 respectively; the second part has 2 digits, 9 and 9 respectively. Calculate Digit Verification of CAS Registry Number 75194-99: (7*7)+(6*5)+(5*1)+(4*9)+(3*4)+(2*9)+(1*9)=159 159 % 10 = 9 So 75194-99-9 is a valid CAS Registry Number.