The CAS Registry Mumber 92406-71-8 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,2,4,0 and 6 respectively; the second part has 2 digits, 7 and 1 respectively. Calculate Digit Verification of CAS Registry Number 92406-71: (7*9)+(6*2)+(5*4)+(4*0)+(3*6)+(2*7)+(1*1)=128 128 % 10 = 8 So 92406-71-8 is a valid CAS Registry Number.