The CAS Registry Mumber 87081-63-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,7,0,8 and 1 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 87081-63: (7*8)+(6*7)+(5*0)+(4*8)+(3*1)+(2*6)+(1*3)=148 148 % 10 = 8 So 87081-63-8 is a valid CAS Registry Number.