The CAS Registry Mumber 35404-57-0 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,5,4,0 and 4 respectively; the second part has 2 digits, 5 and 7 respectively. Calculate Digit Verification of CAS Registry Number 35404-57: (7*3)+(6*5)+(5*4)+(4*0)+(3*4)+(2*5)+(1*7)=100 100 % 10 = 0 So 35404-57-0 is a valid CAS Registry Number.