The CAS Registry Mumber 86365-09-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,6,3,6 and 5 respectively; the second part has 2 digits, 0 and 9 respectively. Calculate Digit Verification of CAS Registry Number 86365-09: (7*8)+(6*6)+(5*3)+(4*6)+(3*5)+(2*0)+(1*9)=155 155 % 10 = 5 So 86365-09-5 is a valid CAS Registry Number.