The CAS Registry Mumber 104417-74-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,4,4,1 and 7 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 104417-74: (8*1)+(7*0)+(6*4)+(5*4)+(4*1)+(3*7)+(2*7)+(1*4)=95 95 % 10 = 5 So 104417-74-5 is a valid CAS Registry Number.