The CAS Registry Mumber 87236-32-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,7,2,3 and 6 respectively; the second part has 2 digits, 3 and 2 respectively. Calculate Digit Verification of CAS Registry Number 87236-32: (7*8)+(6*7)+(5*2)+(4*3)+(3*6)+(2*3)+(1*2)=146 146 % 10 = 6 So 87236-32-6 is a valid CAS Registry Number.