The CAS Registry Mumber 74127-06-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,1,2 and 7 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 74127-06: (7*7)+(6*4)+(5*1)+(4*2)+(3*7)+(2*0)+(1*6)=113 113 % 10 = 3 So 74127-06-3 is a valid CAS Registry Number.