The CAS Registry Mumber 894-64-4 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 8,9 and 4 respectively; the second part has 2 digits, 6 and 4 respectively. Calculate Digit Verification of CAS Registry Number 894-64: (5*8)+(4*9)+(3*4)+(2*6)+(1*4)=104 104 % 10 = 4 So 894-64-4 is a valid CAS Registry Number.