The CAS Registry Mumber 89535-60-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,9,5,3 and 5 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 89535-60: (7*8)+(6*9)+(5*5)+(4*3)+(3*5)+(2*6)+(1*0)=174 174 % 10 = 4 So 89535-60-4 is a valid CAS Registry Number.