The CAS Registry Mumber 73457-29-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,3,4,5 and 7 respectively; the second part has 2 digits, 2 and 9 respectively. Calculate Digit Verification of CAS Registry Number 73457-29: (7*7)+(6*3)+(5*4)+(4*5)+(3*7)+(2*2)+(1*9)=141 141 % 10 = 1 So 73457-29-1 is a valid CAS Registry Number.