The CAS Registry Mumber 29885-38-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,9,8,8 and 5 respectively; the second part has 2 digits, 3 and 8 respectively. Calculate Digit Verification of CAS Registry Number 29885-38: (7*2)+(6*9)+(5*8)+(4*8)+(3*5)+(2*3)+(1*8)=169 169 % 10 = 9 So 29885-38-9 is a valid CAS Registry Number.