The CAS Registry Mumber 111847-84-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,1,8,4 and 7 respectively; the second part has 2 digits, 8 and 4 respectively. Calculate Digit Verification of CAS Registry Number 111847-84: (8*1)+(7*1)+(6*1)+(5*8)+(4*4)+(3*7)+(2*8)+(1*4)=118 118 % 10 = 8 So 111847-84-8 is a valid CAS Registry Number.