Which of the following sets are equal ?
`A={x:x inN,xlt4},B=(1,1,2,3,3},C={1,3},D={x:x` is an odd natural number `lt5} E={1,2,3},F={1,1,3}`

Answer

To determine which of the given sets are equal, we will first express each set in roster form and then compare them.

### Step 1: Write Set A in Roster Form
Set A is defined as:
\[ A = \{ x : x \in \mathbb{N}, x < 4 \} \]
The natural numbers less than 4 are 1, 2, and 3. Therefore:
\[ A = \{ 1, 2, 3 \} \]

### Step 2: Write Set B in Roster Form
Set B is given as:
\[ B = \{ 1, 1, 2, 3, 3 \} \]
In set notation, we only include unique elements. Thus:
\[ B = \{ 1, 2, 3 \} \]

### Step 3: Write Set C in Roster Form
Set C is defined as:
\[ C = \{ 1, 3 \} \]
This set is already in roster form.

### Step 4: Write Set D in Roster Form
Set D is defined as:
\[ D = \{ x : x \text{ is an odd natural number} < 5 \} \]
The odd natural numbers less than 5 are 1 and 3. Therefore:
\[ D = \{ 1, 3 \} \]

### Step 5: Write Set E in Roster Form
Set E is given as:
\[ E = \{ 1, 2, 3 \} \]
This set is already in roster form.

### Step 6: Write Set F in Roster Form
Set F is given as:
\[ F = \{ 1, 1, 3 \} \]
Again, we only include unique elements, so:
\[ F = \{ 1, 3 \} \]

### Step 7: Compare the Sets
Now we have the following sets in roster form:
- \( A = \{ 1, 2, 3 \} \)
- \( B = \{ 1, 2, 3 \} \)
- \( C = \{ 1, 3 \} \)
- \( D = \{ 1, 3 \} \)
- \( E = \{ 1, 2, 3 \} \)
- \( F = \{ 1, 3 \} \)

From the comparison:
- Sets A, B, and E are equal: \( A = B = E = \{ 1, 2, 3 \} \)
- Sets C, D, and F are equal: \( C = D = F = \{ 1, 3 \} \)

### Final Conclusion
The sets that are equal are:
- \( A = B = E \)
- \( C = D = F \)