The CAS Registry Mumber 93164-37-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,3,1,6 and 4 respectively; the second part has 2 digits, 3 and 7 respectively. Calculate Digit Verification of CAS Registry Number 93164-37: (7*9)+(6*3)+(5*1)+(4*6)+(3*4)+(2*3)+(1*7)=135 135 % 10 = 5 So 93164-37-5 is a valid CAS Registry Number.