The CAS Registry Mumber 54562-74-2 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 5,4,5,6 and 2 respectively; the second part has 2 digits, 7 and 4 respectively. Calculate Digit Verification of CAS Registry Number 54562-74: (7*5)+(6*4)+(5*5)+(4*6)+(3*2)+(2*7)+(1*4)=132 132 % 10 = 2 So 54562-74-2 is a valid CAS Registry Number.