NCERT Solutions Class 11 Maths Chapter 1 Sets Exercise 1.1

The NCERT Solutions for Class 11 Maths Chapter 1 Sets Exercise 1.1 cover every question of the first exercise, according to the latest 2026-27 CBSE syllabus. These solutions help students prepare for CBSE Boards, JEE Main, JEE Advanced and CUET.

Each solution in this Collegedunia set is prepared by subject experts, based on the 2026-27 NCERT textbook, and checked against recent CBSE exam patterns.

Exercise 1.1 is where students first meet the idea of a set and learn to write one correctly. The exercise has 6 questions built around these skills:

• Deciding whether a given collection is a well-defined set or not.
• Using the symbols ∈ (belongs to) and ∉ (does not belong to) for elements.
• Switching a set between roster form and set-builder form.

Topics Covered in Exercise 1.1

This exercise introduces the language of sets. A set is a well-defined collection of objects, which means anyone can decide with certainty whether an object is in it. Each object inside a set is called an element or member. Exercise 1.1 keeps the focus on reading, writing and testing this membership.

• Well-defined collections: telling a set (the collection of prime numbers below 10) apart from a vague one (the collection of clever students).
• Roster form: listing all elements inside braces, like A = {1, 2, 3, 4, 5, 6}.
• Set-builder form: stating the common property, like A = {x : x is a natural number less than 7}.
• Membership symbols: writing 2 ∈ A and 8 ∉ A correctly.
• Standard number sets: the letters N, Z, Q, R and what each one stands for.

Important: a collection counts as a set only when the rule for membership is exact. This one idea decides the first question of the exercise.

Question-wise Breakdown of Exercise 1.1

The NCERT Solutions for Class 11 Maths Chapter 1 Sets Exercise 1.1 solve all 6 questions in order. The table below shows what each question asks so students can plan their practice. Full step-by-step answers are inside the PDF above.

Most questions have several parts, so the exercise gives good practice on both forms of writing a set.

Key Formulas and Definitions for Exercise 1.1

Exercise 1.1 has no heavy formulas. It rests on a few clear definitions and the standard letters for number sets. Students should learn these by heart before moving on.

Tip: the letters N, Z, Q and R appear in every later exercise of this chapter, so fixing them now saves time throughout Sets.

Common Mistakes in Exercise 1.1

Students lose easy marks in Exercise 1.1 on small slips of notation. The list below covers the errors that show up most often in class tests on the NCERT Solutions for Class 11 Maths Chapter 1 Sets Exercise 1.1.

• Calling a vague collection a set. "The collection of good cricket players" is not a set because the rule is not exact.
• Mixing up ∈ and ∉. The symbol ∈ is only for a single element, never for another set.
• Repeating an element in roster form. In a set each element is written once, so {1, 2, 2, 3} should be {1, 2, 3}.
• Writing the set-builder rule loosely. Always give the variable and its property clearly, like {x : x is an even natural number}.

Practice Questions for Exercise 1.1

After reading the solutions, students should test themselves on the same question types. The card below opens a set of solved practice questions with step-by-step answers for Exercise 1.1.

Other Exercises of Chapter 1 Sets

Chapter 1 Sets has five exercises plus a Miscellaneous Exercise. Use the table to move to the next exercise once Exercise 1.1 is done.

More Class 11 Maths Sets Resources

Pair the solutions with the notes and the NCERT book PDF for full chapter revision. All three resources for Chapter 1 Sets are linked below.

NCERT Solutions for Other Class 11 Maths Chapters

Students can move to the first exercise of any other Class 11 Maths chapter using the cross-sell table below.

FAQs on NCERT Solutions for Class 11 Maths Chapter 1 Sets Exercise 1.1