The CAS Registry Mumber 74134-06-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,1,3 and 4 respectively; the second part has 2 digits, 0 and 6 respectively. Calculate Digit Verification of CAS Registry Number 74134-06: (7*7)+(6*4)+(5*1)+(4*3)+(3*4)+(2*0)+(1*6)=108 108 % 10 = 8 So 74134-06-8 is a valid CAS Registry Number.