The CAS Registry Mumber 101481-84-9 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,0,1,4,8 and 1 respectively; the second part has 2 digits, 8 and 4 respectively. Calculate Digit Verification of CAS Registry Number 101481-84: (8*1)+(7*0)+(6*1)+(5*4)+(4*8)+(3*1)+(2*8)+(1*4)=89 89 % 10 = 9 So 101481-84-9 is a valid CAS Registry Number.