The CAS Registry Mumber 4029-39-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,0,2 and 9 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 4029-39: (6*4)+(5*0)+(4*2)+(3*9)+(2*3)+(1*9)=74 74 % 10 = 4 So 4029-39-4 is a valid CAS Registry Number.