The CAS Registry Mumber 23182-13-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,3,1,8 and 2 respectively; the second part has 2 digits, 1 and 3 respectively. Calculate Digit Verification of CAS Registry Number 23182-13: (7*2)+(6*3)+(5*1)+(4*8)+(3*2)+(2*1)+(1*3)=80 80 % 10 = 0 So 23182-13-0 is a valid CAS Registry Number.