📘 EXTRA PRACTICE WORKSHEET – SETS

Class XI | CBSE Mathematics

SECTION A: OBJECTIVE TYPE (1 MARK EACH)

1. Fill in the blanks

1. The symbol used to denote “belongs to” is ______
2. The set of all positive integers is denoted by ______
3. A collection which is not well-defined is called a ______ collection.
4. In roster form, repetition of elements is ______
5. The set of all real numbers is denoted by ______

2. Choose the correct option

1. Which of the following is not a set?
   • (a) Collection of vowels in English
   • (b) Collection of even numbers
   • (c) Collection of most intelligent students in a class
   • (d) Collection of prime numbers
2. If \( A = \{1, 3, 5\} \), then which is true?
   • (a) \(2 ∈ A\)
   • (b) \(3 ∉ A\)
   • (c) \(5 ∈ A\)
   • (d) \(1 ∉ A\)

SECTION B: VERY SHORT ANSWER (2 MARKS EACH)

1. Define a set.
2. Write any two examples of well-defined collections.
3. Write the roster form of the set of first five natural numbers.
4. If \( A = \{2, 4, 6, 8\} \), write two elements which do not belong to A.

SECTION C: SHORT ANSWER (3 MARKS EACH)

4. Identify whether the following are sets. Give reasons.

1. Collection of all rivers in India
2. Collection of best movies of the year
3. Collection of all multiples of 5

5. Insert ∈ or ∉

Let

1. 7 ___ A
2. 12 ___ A
3. 0 ___ A
4. 10 ___ A

SECTION D: CONVERSION TYPE (4 MARKS EACH)

6. Write the following in roster form

1. \[ A = \{x : x ∈ Z,\; −2 ≤ x ≤ 4\} \]
2. \[ B = \{x : x ∈ N,\; x² < 30\} \]
3. C = { x : x is a prime number less than 20 }

7. Write the following in set-builder form

1. \(\{4, 8, 12, 16\}\)
2. \(\{1, 4, 9, 16, 25\}\)
3. \(\{3, 6, 9, 12, \ldots\}\)

SECTION E: LISTING ELEMENTS (4 MARKS EACH)

1. \[ A = \{x : x ∈ Z,\; x² ≤ 9\} \]
2. B = { x : x is a month having exactly 30 days }
3. \[ C = \{x : x \text{ is a consonant preceding } m\} \]

SECTION F: MATCH THE FOLLOWING (4 MARKS)

Teacher’s Note: Write steps clearly, avoid repetition in roster form, and always mention the correct domain (N, Z, etc.).