The CAS Registry Mumber 19359-39-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,9,3,5 and 9 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 19359-39: (7*1)+(6*9)+(5*3)+(4*5)+(3*9)+(2*3)+(1*9)=138 138 % 10 = 8 So 19359-39-8 is a valid CAS Registry Number.