The CAS Registry Mumber 74416-82-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,4,1 and 6 respectively; the second part has 2 digits, 8 and 2 respectively. Calculate Digit Verification of CAS Registry Number 74416-82: (7*7)+(6*4)+(5*4)+(4*1)+(3*6)+(2*8)+(1*2)=133 133 % 10 = 3 So 74416-82-3 is a valid CAS Registry Number.