The CAS Registry Mumber 74073-49-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,0,7 and 3 respectively; the second part has 2 digits, 4 and 9 respectively. Calculate Digit Verification of CAS Registry Number 74073-49: (7*7)+(6*4)+(5*0)+(4*7)+(3*3)+(2*4)+(1*9)=127 127 % 10 = 7 So 74073-49-7 is a valid CAS Registry Number.