The CAS Registry Mumber 51549-35-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,1,5,4 and 9 respectively; the second part has 2 digits, 3 and 5 respectively. Calculate Digit Verification of CAS Registry Number 51549-35: (7*5)+(6*1)+(5*5)+(4*4)+(3*9)+(2*3)+(1*5)=120 120 % 10 = 0 So 51549-35-0 is a valid CAS Registry Number.