The CAS Registry Mumber 128465-12-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,8,4,6 and 5 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 128465-12: (8*1)+(7*2)+(6*8)+(5*4)+(4*6)+(3*5)+(2*1)+(1*2)=133 133 % 10 = 3 So 128465-12-3 is a valid CAS Registry Number.