The CAS Registry Mumber 72290-22-3 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, 2 and 2 respectively. Calculate Digit Verification of CAS Registry Number 72290-22: (7*7)+(6*2)+(5*2)+(4*9)+(3*0)+(2*2)+(1*2)=113 113 % 10 = 3 So 72290-22-3 is a valid CAS Registry Number.