The CAS Registry Mumber 383159-58-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 3,8,3,1,5 and 9 respectively; the second part has 2 digits, 5 and 8 respectively. Calculate Digit Verification of CAS Registry Number 383159-58: (8*3)+(7*8)+(6*3)+(5*1)+(4*5)+(3*9)+(2*5)+(1*8)=168 168 % 10 = 8 So 383159-58-8 is a valid CAS Registry Number.