The CAS Registry Mumber 74596-93-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,5,9 and 6 respectively; the second part has 2 digits, 9 and 3 respectively. Calculate Digit Verification of CAS Registry Number 74596-93: (7*7)+(6*4)+(5*5)+(4*9)+(3*6)+(2*9)+(1*3)=173 173 % 10 = 3 So 74596-93-3 is a valid CAS Registry Number.