The CAS Registry Mumber 81038-46-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,1,0,3 and 8 respectively; the second part has 2 digits, 4 and 6 respectively. Calculate Digit Verification of CAS Registry Number 81038-46: (7*8)+(6*1)+(5*0)+(4*3)+(3*8)+(2*4)+(1*6)=112 112 % 10 = 2 So 81038-46-2 is a valid CAS Registry Number.