The CAS Registry Mumber 159579-96-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,5,9,5,7 and 9 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 159579-96: (8*1)+(7*5)+(6*9)+(5*5)+(4*7)+(3*9)+(2*9)+(1*6)=201 201 % 10 = 1 So 159579-96-1 is a valid CAS Registry Number.