The CAS Registry Mumber 28229-47-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,8,2,2 and 9 respectively; the second part has 2 digits, 4 and 7 respectively. Calculate Digit Verification of CAS Registry Number 28229-47: (7*2)+(6*8)+(5*2)+(4*2)+(3*9)+(2*4)+(1*7)=122 122 % 10 = 2 So 28229-47-2 is a valid CAS Registry Number.