Real Numbers — Chapter Overview
What Class 10 Real Numbers covers, why it matters, and how the chapter is usually asked in the CBSE board exam.
About 6 min readReviewed by a CBSE Mathematics teacherSyllabus 2024-25Updated 6/8/2026
Real Numbers is the first chapter of Class 10 Mathematics. It looks small, but it quietly supports the whole number system you will use for the rest of the year.
What you will learn
- The Fundamental Theorem of Arithmetic
- Finding HCF and LCM using prime factorisation
- Proving that numbers such as √2 are irrational
- Fundamental Theorem of Arithmetic
- Every composite number can be expressed as a product of primes, and this factorisation is unique apart from the order of the factors.
How to study this chapter
- Read the overview and the concept lesson
- Work through the worked examples yourself on paper
- Attempt the practice quiz
- Revisit only the questions you got wrong
Quick recap
- Prime factorisation is unique
- HCF × LCM = product of the two numbers
- √2, √3 and √5 are irrational