The CAS Registry Mumber 64034-75-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 6,4,0,3 and 4 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 64034-75: (7*6)+(6*4)+(5*0)+(4*3)+(3*4)+(2*7)+(1*5)=109 109 % 10 = 9 So 64034-75-9 is a valid CAS Registry Number.