The CAS Registry Mumber 86447-18-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,4,4 and 7 respectively; the second part has 2 digits, 1 and 8 respectively. Calculate Digit Verification of CAS Registry Number 86447-18: (7*8)+(6*6)+(5*4)+(4*4)+(3*7)+(2*1)+(1*8)=159 159 % 10 = 9 So 86447-18-9 is a valid CAS Registry Number.