The CAS Registry Mumber 57180-01-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,7,1,8 and 0 respectively; the second part has 2 digits, 0 and 1 respectively. Calculate Digit Verification of CAS Registry Number 57180-01: (7*5)+(6*7)+(5*1)+(4*8)+(3*0)+(2*0)+(1*1)=115 115 % 10 = 5 So 57180-01-5 is a valid CAS Registry Number.