A = x is a natural number. And x is less than 3

So all natural numbers less than 3 constitute set A.

{1, 2}

A ={1, 2}

B = {1, 2}

C = {1, 3}

D = x is a natural number. And x is less than 5 and is odd.

So all odd natural numbers less than 5 constitute set D.

{1, 3}

D = {1, 3}

E ={1, 2, 1, 1}

We don’t repeat same elements in a set.

∴ E = {1, 2}

F ={1, 1, 3}

We don’t repeat same elements in a set.

∴ F = {1, 3}

∴ A = {1, 2}

B = {1, 2}

C = {1, 3}

D = {1, 3}

E = {1, 2}

F = {1, 3}

Now, we can see clearly that set A, B, E are equal and set C, D, F are equal.