The CAS Registry Mumber 41297-12-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,1,2,9 and 7 respectively; the second part has 2 digits, 1 and 2 respectively. Calculate Digit Verification of CAS Registry Number 41297-12: (7*4)+(6*1)+(5*2)+(4*9)+(3*7)+(2*1)+(1*2)=105 105 % 10 = 5 So 41297-12-5 is a valid CAS Registry Number.