The CAS Registry Mumber 57765-00-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,7,7,6 and 5 respectively; the second part has 2 digits, 0 and 0 respectively. Calculate Digit Verification of CAS Registry Number 57765-00: (7*5)+(6*7)+(5*7)+(4*6)+(3*5)+(2*0)+(1*0)=151 151 % 10 = 1 So 57765-00-1 is a valid CAS Registry Number.