The CAS Registry Mumber 7276-63-3 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,2,7 and 6 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 7276-63: (6*7)+(5*2)+(4*7)+(3*6)+(2*6)+(1*3)=113 113 % 10 = 3 So 7276-63-3 is a valid CAS Registry Number.