The CAS Registry Mumber 6585-06-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 6,5,8 and 5 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 6585-06: (6*6)+(5*5)+(4*8)+(3*5)+(2*0)+(1*6)=114 114 % 10 = 4 So 6585-06-4 is a valid CAS Registry Number.