The CAS Registry Mumber 57340-39-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,7,3,4 and 0 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 57340-39: (7*5)+(6*7)+(5*3)+(4*4)+(3*0)+(2*3)+(1*9)=123 123 % 10 = 3 So 57340-39-3 is a valid CAS Registry Number.