The CAS Registry Mumber 97773-03-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,7,7,7 and 3 respectively; the second part has 2 digits, 0 and 3 respectively. Calculate Digit Verification of CAS Registry Number 97773-03: (7*9)+(6*7)+(5*7)+(4*7)+(3*3)+(2*0)+(1*3)=180 180 % 10 = 0 So 97773-03-0 is a valid CAS Registry Number.