The CAS Registry Mumber 75948-66-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 7,5,9,4 and 8 respectively; the second part has 2 digits, 6 and 6 respectively. Calculate Digit Verification of CAS Registry Number 75948-66: (7*7)+(6*5)+(5*9)+(4*4)+(3*8)+(2*6)+(1*6)=182 182 % 10 = 2 So 75948-66-2 is a valid CAS Registry Number.