The CAS Registry Mumber 74985-65-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,4,9,8 and 5 respectively; the second part has 2 digits, 6 and 5 respectively. Calculate Digit Verification of CAS Registry Number 74985-65: (7*7)+(6*4)+(5*9)+(4*8)+(3*5)+(2*6)+(1*5)=182 182 % 10 = 2 So 74985-65-2 is a valid CAS Registry Number.