The CAS Registry Mumber 1908-03-8 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,9,0 and 8 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 1908-03: (6*1)+(5*9)+(4*0)+(3*8)+(2*0)+(1*3)=78 78 % 10 = 8 So 1908-03-8 is a valid CAS Registry Number.