The CAS Registry Mumber 124841-96-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,4,8,4 and 1 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 124841-96: (8*1)+(7*2)+(6*4)+(5*8)+(4*4)+(3*1)+(2*9)+(1*6)=129 129 % 10 = 9 So 124841-96-9 is a valid CAS Registry Number.