The CAS Registry Mumber 89949-93-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,9,9,4 and 9 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 89949-93: (7*8)+(6*9)+(5*9)+(4*4)+(3*9)+(2*9)+(1*3)=219 219 % 10 = 9 So 89949-93-9 is a valid CAS Registry Number.