The CAS Registry Mumber 88818-40-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,8,8,1 and 8 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 88818-40: (7*8)+(6*8)+(5*8)+(4*1)+(3*8)+(2*4)+(1*0)=180 180 % 10 = 0 So 88818-40-0 is a valid CAS Registry Number.