The CAS Registry Mumber 117269-75-7 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,7,2,6 and 9 respectively; the second part has 2 digits, 7 and 5 respectively. Calculate Digit Verification of CAS Registry Number 117269-75: (8*1)+(7*1)+(6*7)+(5*2)+(4*6)+(3*9)+(2*7)+(1*5)=137 137 % 10 = 7 So 117269-75-7 is a valid CAS Registry Number.