The CAS Registry Mumber 40249-24-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,0,2,4 and 9 respectively; the second part has 2 digits, 2 and 4 respectively. Calculate Digit Verification of CAS Registry Number 40249-24: (7*4)+(6*0)+(5*2)+(4*4)+(3*9)+(2*2)+(1*4)=89 89 % 10 = 9 So 40249-24-9 is a valid CAS Registry Number.