The CAS Registry Mumber 76073-57-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,6,0,7 and 3 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 76073-57: (7*7)+(6*6)+(5*0)+(4*7)+(3*3)+(2*5)+(1*7)=139 139 % 10 = 9 So 76073-57-9 is a valid CAS Registry Number.