The CAS Registry Mumber 103383-63-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,3,3,8 and 3 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 103383-63: (8*1)+(7*0)+(6*3)+(5*3)+(4*8)+(3*3)+(2*6)+(1*3)=97 97 % 10 = 7 So 103383-63-7 is a valid CAS Registry Number.