The CAS Registry Mumber 129959-02-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,9,9,5 and 9 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 129959-02: (8*1)+(7*2)+(6*9)+(5*9)+(4*5)+(3*9)+(2*0)+(1*2)=170 170 % 10 = 0 So 129959-02-0 is a valid CAS Registry Number.