The CAS Registry Mumber 1457-31-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,4,5 and 7 respectively; the second part has 2 digits, 3 and 1 respectively. Calculate Digit Verification of CAS Registry Number 1457-31: (6*1)+(5*4)+(4*5)+(3*7)+(2*3)+(1*1)=74 74 % 10 = 4 So 1457-31-4 is a valid CAS Registry Number.