The CAS Registry Mumber 89989-32-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,9,9,8 and 9 respectively; the second part has 2 digits, 3 and 2 respectively. Calculate Digit Verification of CAS Registry Number 89989-32: (7*8)+(6*9)+(5*9)+(4*8)+(3*9)+(2*3)+(1*2)=222 222 % 10 = 2 So 89989-32-2 is a valid CAS Registry Number.