The CAS Registry Mumber 110612-90-3 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,0,6,1 and 2 respectively; the second part has 2 digits, 9 and 0 respectively. Calculate Digit Verification of CAS Registry Number 110612-90: (8*1)+(7*1)+(6*0)+(5*6)+(4*1)+(3*2)+(2*9)+(1*0)=73 73 % 10 = 3 So 110612-90-3 is a valid CAS Registry Number.