The CAS Registry Mumber 130089-61-1 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,0,0,8 and 9 respectively; the second part has 2 digits, 6 and 1 respectively. Calculate Digit Verification of CAS Registry Number 130089-61: (8*1)+(7*3)+(6*0)+(5*0)+(4*8)+(3*9)+(2*6)+(1*1)=101 101 % 10 = 1 So 130089-61-1 is a valid CAS Registry Number.