The CAS Registry Mumber 4301-39-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,3,0 and 1 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 4301-39: (6*4)+(5*3)+(4*0)+(3*1)+(2*3)+(1*9)=57 57 % 10 = 7 So 4301-39-7 is a valid CAS Registry Number.