The CAS Registry Mumber 126314-71-4 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 1,2,6,3,1 and 4 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 126314-71: (8*1)+(7*2)+(6*6)+(5*3)+(4*1)+(3*4)+(2*7)+(1*1)=104 104 % 10 = 4 So 126314-71-4 is a valid CAS Registry Number.