The CAS Registry Mumber 72290-05-2 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 5 respectively. Calculate Digit Verification of CAS Registry Number 72290-05: (7*7)+(6*2)+(5*2)+(4*9)+(3*0)+(2*0)+(1*5)=112 112 % 10 = 2 So 72290-05-2 is a valid CAS Registry Number.