The CAS Registry Mumber 62541-63-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,2,5,4 and 1 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 62541-63: (7*6)+(6*2)+(5*5)+(4*4)+(3*1)+(2*6)+(1*3)=113 113 % 10 = 3 So 62541-63-3 is a valid CAS Registry Number.