The CAS Registry Mumber 86255-36-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,2,5 and 5 respectively; the second part has 2 digits, 3 and 6 respectively. Calculate Digit Verification of CAS Registry Number 86255-36: (7*8)+(6*6)+(5*2)+(4*5)+(3*5)+(2*3)+(1*6)=149 149 % 10 = 9 So 86255-36-9 is a valid CAS Registry Number.