The CAS Registry Mumber 497833-40-6 includes 9 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 6 digits, 4,9,7,8,3 and 3 respectively; the second part has 2 digits, 4 and 0 respectively. Calculate Digit Verification of CAS Registry Number 497833-40: (8*4)+(7*9)+(6*7)+(5*8)+(4*3)+(3*3)+(2*4)+(1*0)=206 206 % 10 = 6 So 497833-40-6 is a valid CAS Registry Number.