The CAS Registry Mumber 117693-36-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,1,7,6,9 and 3 respectively; the second part has 2 digits, 3 and 6 respectively. Calculate Digit Verification of CAS Registry Number 117693-36: (8*1)+(7*1)+(6*7)+(5*6)+(4*9)+(3*3)+(2*3)+(1*6)=144 144 % 10 = 4 So 117693-36-4 is a valid CAS Registry Number.