The CAS Registry Mumber 84811-75-6 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,4,8,1 and 1 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 84811-75: (7*8)+(6*4)+(5*8)+(4*1)+(3*1)+(2*7)+(1*5)=146 146 % 10 = 6 So 84811-75-6 is a valid CAS Registry Number.