The CAS Registry Mumber 58599-04-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,8,5,9 and 9 respectively; the second part has 2 digits, 0 and 4 respectively. Calculate Digit Verification of CAS Registry Number 58599-04: (7*5)+(6*8)+(5*5)+(4*9)+(3*9)+(2*0)+(1*4)=175 175 % 10 = 5 So 58599-04-5 is a valid CAS Registry Number.