The CAS Registry Mumber 53604-92-5 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,3,6,0 and 4 respectively; the second part has 2 digits, 9 and 2 respectively. Calculate Digit Verification of CAS Registry Number 53604-92: (7*5)+(6*3)+(5*6)+(4*0)+(3*4)+(2*9)+(1*2)=115 115 % 10 = 5 So 53604-92-5 is a valid CAS Registry Number.