The CAS Registry Mumber 94934-78-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,9,3 and 4 respectively; the second part has 2 digits, 7 and 8 respectively. Calculate Digit Verification of CAS Registry Number 94934-78: (7*9)+(6*4)+(5*9)+(4*3)+(3*4)+(2*7)+(1*8)=178 178 % 10 = 8 So 94934-78-8 is a valid CAS Registry Number.