The CAS Registry Mumber 630419-17-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 6,3,0,4,1 and 9 respectively; the second part has 2 digits, 1 and 7 respectively. Calculate Digit Verification of CAS Registry Number 630419-17: (8*6)+(7*3)+(6*0)+(5*4)+(4*1)+(3*9)+(2*1)+(1*7)=129 129 % 10 = 9 So 630419-17-9 is a valid CAS Registry Number.