The CAS Registry Mumber 4195-75-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,1,9 and 5 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 4195-75: (6*4)+(5*1)+(4*9)+(3*5)+(2*7)+(1*5)=99 99 % 10 = 9 So 4195-75-9 is a valid CAS Registry Number.