The CAS Registry Mumber 2892-39-9 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 2,8,9 and 2 respectively; the second part has 2 digits, 3 and 9 respectively. Calculate Digit Verification of CAS Registry Number 2892-39: (6*2)+(5*8)+(4*9)+(3*2)+(2*3)+(1*9)=109 109 % 10 = 9 So 2892-39-9 is a valid CAS Registry Number.