The CAS Registry Mumber 24290-16-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 2,4,2,9 and 0 respectively; the second part has 2 digits, 1 and 6 respectively. Calculate Digit Verification of CAS Registry Number 24290-16: (7*2)+(6*4)+(5*2)+(4*9)+(3*0)+(2*1)+(1*6)=92 92 % 10 = 2 So 24290-16-2 is a valid CAS Registry Number.