The CAS Registry Mumber 51225-41-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,1,2,2 and 5 respectively; the second part has 2 digits, 4 and 1 respectively. Calculate Digit Verification of CAS Registry Number 51225-41: (7*5)+(6*1)+(5*2)+(4*2)+(3*5)+(2*4)+(1*1)=83 83 % 10 = 3 So 51225-41-3 is a valid CAS Registry Number.