The CAS Registry Mumber 104636-46-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,4,6,3 and 6 respectively; the second part has 2 digits, 4 and 6 respectively. Calculate Digit Verification of CAS Registry Number 104636-46: (8*1)+(7*0)+(6*4)+(5*6)+(4*3)+(3*6)+(2*4)+(1*6)=106 106 % 10 = 6 So 104636-46-6 is a valid CAS Registry Number.