The CAS Registry Mumber 1189106-86-2 includes 10 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 7 digits, 1,1,8,9,1,0 and 6 respectively; the second part has 2 digits, 8 and 6 respectively. Calculate Digit Verification of CAS Registry Number 1189106-86: (9*1)+(8*1)+(7*8)+(6*9)+(5*1)+(4*0)+(3*6)+(2*8)+(1*6)=172 172 % 10 = 2 So 1189106-86-2 is a valid CAS Registry Number.