The CAS Registry Mumber 183274-22-8 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,8,3,2,7 and 4 respectively; the second part has 2 digits, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 183274-22: (8*1)+(7*8)+(6*3)+(5*2)+(4*7)+(3*4)+(2*2)+(1*2)=138 138 % 10 = 8 So 183274-22-8 is a valid CAS Registry Number.