The CAS Registry Mumber 95303-72-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,5,3,0 and 3 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 95303-72: (7*9)+(6*5)+(5*3)+(4*0)+(3*3)+(2*7)+(1*2)=133 133 % 10 = 3 So 95303-72-3 is a valid CAS Registry Number.