The CAS Registry Mumber 133009-64-0 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,3,3,0,0 and 9 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 133009-64: (8*1)+(7*3)+(6*3)+(5*0)+(4*0)+(3*9)+(2*6)+(1*4)=90 90 % 10 = 0 So 133009-64-0 is a valid CAS Registry Number.