The CAS Registry Mumber 38255-89-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,8,2,5 and 5 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 38255-89: (7*3)+(6*8)+(5*2)+(4*5)+(3*5)+(2*8)+(1*9)=139 139 % 10 = 9 So 38255-89-9 is a valid CAS Registry Number.