The CAS Registry Mumber 94320-77-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,3,2 and 0 respectively; the second part has 2 digits, 7 and 7 respectively. Calculate Digit Verification of CAS Registry Number 94320-77: (7*9)+(6*4)+(5*3)+(4*2)+(3*0)+(2*7)+(1*7)=131 131 % 10 = 1 So 94320-77-1 is a valid CAS Registry Number.