The CAS Registry Mumber 115589-64-5 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,5,5,8 and 9 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 115589-64: (8*1)+(7*1)+(6*5)+(5*5)+(4*8)+(3*9)+(2*6)+(1*4)=145 145 % 10 = 5 So 115589-64-5 is a valid CAS Registry Number.