The CAS Registry Mumber 39113-25-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,9,1,1 and 3 respectively; the second part has 2 digits, 2 and 5 respectively. Calculate Digit Verification of CAS Registry Number 39113-25: (7*3)+(6*9)+(5*1)+(4*1)+(3*3)+(2*2)+(1*5)=102 102 % 10 = 2 So 39113-25-2 is a valid CAS Registry Number.