The CAS Registry Mumber 111822-81-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,1,8,2 and 2 respectively; the second part has 2 digits, 8 and 1 respectively. Calculate Digit Verification of CAS Registry Number 111822-81: (8*1)+(7*1)+(6*1)+(5*8)+(4*2)+(3*2)+(2*8)+(1*1)=92 92 % 10 = 2 So 111822-81-2 is a valid CAS Registry Number.