The CAS Registry Mumber 4041-94-5 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 4,0,4 and 1 respectively; the second part has 2 digits, 9 and 4 respectively. Calculate Digit Verification of CAS Registry Number 4041-94: (6*4)+(5*0)+(4*4)+(3*1)+(2*9)+(1*4)=65 65 % 10 = 5 So 4041-94-5 is a valid CAS Registry Number.