The CAS Registry Mumber 885268-84-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 8,8,5,2,6 and 8 respectively; the second part has 2 digits, 8 and 4 respectively. Calculate Digit Verification of CAS Registry Number 885268-84: (8*8)+(7*8)+(6*5)+(5*2)+(4*6)+(3*8)+(2*8)+(1*4)=228 228 % 10 = 8 So 885268-84-8 is a valid CAS Registry Number.