The CAS Registry Mumber 25126-62-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,5,1,2 and 6 respectively; the second part has 2 digits, 6 and 2 respectively. Calculate Digit Verification of CAS Registry Number 25126-62: (7*2)+(6*5)+(5*1)+(4*2)+(3*6)+(2*6)+(1*2)=89 89 % 10 = 9 So 25126-62-9 is a valid CAS Registry Number.