The CAS Registry Mumber 125459-20-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,5,4,5 and 9 respectively; the second part has 2 digits, 2 and 0 respectively. Calculate Digit Verification of CAS Registry Number 125459-20: (8*1)+(7*2)+(6*5)+(5*4)+(4*5)+(3*9)+(2*2)+(1*0)=123 123 % 10 = 3 So 125459-20-3 is a valid CAS Registry Number.