The CAS Registry Mumber 34321-60-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,4,3,2 and 1 respectively; the second part has 2 digits, 6 and 0 respectively. Calculate Digit Verification of CAS Registry Number 34321-60: (7*3)+(6*4)+(5*3)+(4*2)+(3*1)+(2*6)+(1*0)=83 83 % 10 = 3 So 34321-60-3 is a valid CAS Registry Number.