The CAS Registry Mumber 113211-52-2 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,3,2,1 and 1 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 113211-52: (8*1)+(7*1)+(6*3)+(5*2)+(4*1)+(3*1)+(2*5)+(1*2)=62 62 % 10 = 2 So 113211-52-2 is a valid CAS Registry Number.