The CAS Registry Mumber 94897-23-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,4,8,9 and 7 respectively; the second part has 2 digits, 2 and 3 respectively. Calculate Digit Verification of CAS Registry Number 94897-23: (7*9)+(6*4)+(5*8)+(4*9)+(3*7)+(2*2)+(1*3)=191 191 % 10 = 1 So 94897-23-1 is a valid CAS Registry Number.