The CAS Registry Mumber 97406-83-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 9,7,4,0 and 6 respectively; the second part has 2 digits, 8 and 3 respectively. Calculate Digit Verification of CAS Registry Number 97406-83: (7*9)+(6*7)+(5*4)+(4*0)+(3*6)+(2*8)+(1*3)=162 162 % 10 = 2 So 97406-83-2 is a valid CAS Registry Number.