The CAS Registry Mumber 75882-52-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,8,8 and 2 respectively; the second part has 2 digits, 5 and 2 respectively. Calculate Digit Verification of CAS Registry Number 75882-52: (7*7)+(6*5)+(5*8)+(4*8)+(3*2)+(2*5)+(1*2)=169 169 % 10 = 9 So 75882-52-9 is a valid CAS Registry Number.