The CAS Registry Mumber 87466-13-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,7,4,6 and 6 respectively; the second part has 2 digits, 1 and 3 respectively. Calculate Digit Verification of CAS Registry Number 87466-13: (7*8)+(6*7)+(5*4)+(4*6)+(3*6)+(2*1)+(1*3)=165 165 % 10 = 5 So 87466-13-5 is a valid CAS Registry Number.