The CAS Registry Mumber 83599-16-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,3,5,9 and 9 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 83599-16: (7*8)+(6*3)+(5*5)+(4*9)+(3*9)+(2*1)+(1*6)=170 170 % 10 = 0 So 83599-16-0 is a valid CAS Registry Number.