The CAS Registry Mumber 497066-72-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 4,9,7,0,6 and 6 respectively; the second part has 2 digits, 7 and 2 respectively. Calculate Digit Verification of CAS Registry Number 497066-72: (8*4)+(7*9)+(6*7)+(5*0)+(4*6)+(3*6)+(2*7)+(1*2)=195 195 % 10 = 5 So 497066-72-5 is a valid CAS Registry Number.