The CAS Registry Mumber 49588-66-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 4,9,5,8 and 8 respectively; the second part has 2 digits, 6 and 6 respectively. Calculate Digit Verification of CAS Registry Number 49588-66: (7*4)+(6*9)+(5*5)+(4*8)+(3*8)+(2*6)+(1*6)=181 181 % 10 = 1 So 49588-66-1 is a valid CAS Registry Number.