The CAS Registry Mumber 117018-89-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,7,0,1 and 8 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 117018-89: (8*1)+(7*1)+(6*7)+(5*0)+(4*1)+(3*8)+(2*8)+(1*9)=110 110 % 10 = 0 So 117018-89-0 is a valid CAS Registry Number.