The CAS Registry Mumber 125419-72-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,5,4,1 and 9 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 125419-72: (8*1)+(7*2)+(6*5)+(5*4)+(4*1)+(3*9)+(2*7)+(1*2)=119 119 % 10 = 9 So 125419-72-9 is a valid CAS Registry Number.