The CAS Registry Mumber 132038-66-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,2,0,3 and 8 respectively; the second part has 2 digits, 6 and 6 respectively. Calculate Digit Verification of CAS Registry Number 132038-66: (8*1)+(7*3)+(6*2)+(5*0)+(4*3)+(3*8)+(2*6)+(1*6)=95 95 % 10 = 5 So 132038-66-5 is a valid CAS Registry Number.