The CAS Registry Mumber 94856-81-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,8,5 and 6 respectively; the second part has 2 digits, 8 and 1 respectively. Calculate Digit Verification of CAS Registry Number 94856-81: (7*9)+(6*4)+(5*8)+(4*5)+(3*6)+(2*8)+(1*1)=182 182 % 10 = 2 So 94856-81-2 is a valid CAS Registry Number.