The CAS Registry Mumber 89539-02-6 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 9 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 89539-02: (7*8)+(6*9)+(5*5)+(4*3)+(3*9)+(2*0)+(1*2)=176 176 % 10 = 6 So 89539-02-6 is a valid CAS Registry Number.