The CAS Registry Mumber 73261-75-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,3,2,6 and 1 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 73261-75: (7*7)+(6*3)+(5*2)+(4*6)+(3*1)+(2*7)+(1*5)=123 123 % 10 = 3 So 73261-75-3 is a valid CAS Registry Number.