The CAS Registry Mumber 19419-40-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,9,4,1 and 9 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 19419-40: (7*1)+(6*9)+(5*4)+(4*1)+(3*9)+(2*4)+(1*0)=120 120 % 10 = 0 So 19419-40-0 is a valid CAS Registry Number.