The CAS Registry Mumber 93764-89-7 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,3,7,6 and 4 respectively; the second part has 2 digits, 8 and 9 respectively. Calculate Digit Verification of CAS Registry Number 93764-89: (7*9)+(6*3)+(5*7)+(4*6)+(3*4)+(2*8)+(1*9)=177 177 % 10 = 7 So 93764-89-7 is a valid CAS Registry Number.