The CAS Registry Mumber 54370-02-4 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,4,3,7 and 0 respectively; the second part has 2 digits, 0 and 2 respectively. Calculate Digit Verification of CAS Registry Number 54370-02: (7*5)+(6*4)+(5*3)+(4*7)+(3*0)+(2*0)+(1*2)=104 104 % 10 = 4 So 54370-02-4 is a valid CAS Registry Number.