The CAS Registry Mumber 1579-57-3 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 1,5,7 and 9 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 1579-57: (6*1)+(5*5)+(4*7)+(3*9)+(2*5)+(1*7)=103 103 % 10 = 3 So 1579-57-3 is a valid CAS Registry Number.