The CAS Registry Mumber 5773-63-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 5,7,7 and 3 respectively; the second part has 2 digits, 6 and 3 respectively. Calculate Digit Verification of CAS Registry Number 5773-63: (6*5)+(5*7)+(4*7)+(3*3)+(2*6)+(1*3)=117 117 % 10 = 7 So 5773-63-7 is a valid CAS Registry Number.