The CAS Registry Mumber 72290-02-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,2,2,9 and 0 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 72290-02: (7*7)+(6*2)+(5*2)+(4*9)+(3*0)+(2*0)+(1*2)=109 109 % 10 = 9 So 72290-02-9 is a valid CAS Registry Number.