The CAS Registry Mumber 37504-45-3 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 3,7,5,0 and 4 respectively; the second part has 2 digits, 4 and 5 respectively. Calculate Digit Verification of CAS Registry Number 37504-45: (7*3)+(6*7)+(5*5)+(4*0)+(3*4)+(2*4)+(1*5)=113 113 % 10 = 3 So 37504-45-3 is a valid CAS Registry Number.