The CAS Registry Mumber 111466-56-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,1,4,6 and 6 respectively; the second part has 2 digits, 5 and 6 respectively. Calculate Digit Verification of CAS Registry Number 111466-56: (8*1)+(7*1)+(6*1)+(5*4)+(4*6)+(3*6)+(2*5)+(1*6)=99 99 % 10 = 9 So 111466-56-9 is a valid CAS Registry Number.