The CAS Registry Mumber 147809-04-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,4,7,8,0 and 9 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 147809-04: (8*1)+(7*4)+(6*7)+(5*8)+(4*0)+(3*9)+(2*0)+(1*4)=149 149 % 10 = 9 So 147809-04-9 is a valid CAS Registry Number.