The CAS Registry Mumber 52772-37-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,2,7,7 and 2 respectively; the second part has 2 digits, 3 and 7 respectively. Calculate Digit Verification of CAS Registry Number 52772-37: (7*5)+(6*2)+(5*7)+(4*7)+(3*2)+(2*3)+(1*7)=129 129 % 10 = 9 So 52772-37-9 is a valid CAS Registry Number.