The CAS Registry Mumber 77472-73-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,7,4,7 and 2 respectively; the second part has 2 digits, 7 and 3 respectively. Calculate Digit Verification of CAS Registry Number 77472-73: (7*7)+(6*7)+(5*4)+(4*7)+(3*2)+(2*7)+(1*3)=162 162 % 10 = 2 So 77472-73-2 is a valid CAS Registry Number.