The CAS Registry Mumber 57055-35-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,7,0,5 and 5 respectively; the second part has 2 digits, 3 and 5 respectively. Calculate Digit Verification of CAS Registry Number 57055-35: (7*5)+(6*7)+(5*0)+(4*5)+(3*5)+(2*3)+(1*5)=123 123 % 10 = 3 So 57055-35-3 is a valid CAS Registry Number.