The CAS Registry Mumber 130489-65-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,0,4,8 and 9 respectively; the second part has 2 digits, 6 and 5 respectively. Calculate Digit Verification of CAS Registry Number 130489-65: (8*1)+(7*3)+(6*0)+(5*4)+(4*8)+(3*9)+(2*6)+(1*5)=125 125 % 10 = 5 So 130489-65-5 is a valid CAS Registry Number.