The CAS Registry Mumber 183296-89-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,8,3,2,9 and 6 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 183296-89: (8*1)+(7*8)+(6*3)+(5*2)+(4*9)+(3*6)+(2*8)+(1*9)=171 171 % 10 = 1 So 183296-89-1 is a valid CAS Registry Number.