The CAS Registry Mumber 12738-03-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,2,7,3 and 8 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 12738-03: (7*1)+(6*2)+(5*7)+(4*3)+(3*8)+(2*0)+(1*3)=93 93 % 10 = 3 So 12738-03-3 is a valid CAS Registry Number.