The CAS Registry Mumber 43066-18-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,3,0,6 and 6 respectively; the second part has 2 digits, 1 and 8 respectively. Calculate Digit Verification of CAS Registry Number 43066-18: (7*4)+(6*3)+(5*0)+(4*6)+(3*6)+(2*1)+(1*8)=98 98 % 10 = 8 So 43066-18-8 is a valid CAS Registry Number.