By the end of this chapter you'll be able to…

  • 1Arrange things in a sensible order
  • 2Explain an iterative process
  • 3Apply Euclid's division algorithm for the HCF
  • 4Understand Euclid's game
  • 5Follow step-by-step procedures
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Why this chapter matters
Ordering data and following step-by-step algorithms like Euclid's are key reasoning and computing skills. These are tested in the TN Class 6 Term 3 exam and build algorithmic thinking.

Before you start — revise these

A 5-minute refresher here will save you 30 minutes of confusion below.

Information Processing (Ordering and Algorithms) — Class 6 Maths (Samacheer Kalvi)

TN State Board (Samacheer Kalvi) Class 6 Mathematics, Term 3 — Chapter 5. Ordering, repeating steps and Euclid's algorithm.


1. About this chapter

This chapter covers arranging things in order, iterative (repeating) processes, Euclid's division algorithm for the HCF, and Euclid's game.

2. Arranging and ordering

  • Arranging things in order (smallest to largest or by a rule) makes information easy to find and compare — like a dictionary or a class list.
  • A clear order avoids confusion and helps in searching and sorting.

3. Iterative processes

  • An iterative process is one that repeats the same step again and again until a condition is met.
  • Example: repeatedly subtracting or dividing until you reach a stopping point — each repeat is one iteration.

4. Euclid's division algorithm and game

  • Euclid's division algorithm finds the HCF of two numbers by repeated division:
    1. Divide the larger by the smaller and note the remainder.
    2. Replace the larger by the smaller and the smaller by the remainder.
    3. Repeat until the remainder is 0; the last divisor is the HCF.
  • Euclid's game is a number game based on repeatedly subtracting multiples — an iterative process that also leads to the HCF.

5. Worked examples

Example 1. Use Euclid's algorithm to find the HCF of 48 and 18. 48 = 18 × 2 + 12; 18 = 12 × 1 + 6; 12 = 6 × 2 + 0 → HCF = 6.

Example 2. What is an iterative process? One that repeats the same step until a condition is met.

Example 3. Arrange in ascending order: 34, 12, 27, 8. 8, 12, 27, 34.

6. Exercises (Samacheer Kalvi)

  1. Arrange in descending order: 56, 23, 78, 9, 41.
  2. Use Euclid's division algorithm to find the HCF of 36 and 24.
  3. Find the HCF of 60 and 48 by repeated division.
  4. Describe one everyday example of an iterative process.
  5. Sort the names Asha, Ravi, Bala, Kavi in alphabetical order.

7. Common mistakes

  • Mistake: Stopping Euclid's algorithm before the remainder is 0. Fix: Keep dividing until the remainder is 0; the last divisor is the HCF.
  • Mistake: Taking the last remainder (0) as the HCF. Fix: The HCF is the last non-zero divisor, not the 0 remainder.
  • Mistake: Ordering carelessly. Fix: Use a clear rule (size or alphabetical) and check each item.

8. Quick revision

  • Term 3 · Ch 5 · ordering and algorithms.
  • Arranging in order makes information easy to find and compare.
  • An iterative process repeats the same step until a condition is met.
  • Euclid's algorithm: divide, replace, repeat until remainder 0; the last divisor is the HCF.

Key formulas & results

Everything you need to memorise, in one card. Screenshot this for revision.

Ordering
arrange by size or by rule (alphabetical)
Easy to search.
Iterative process
repeat the same step until a condition is met
Each repeat = an iteration.
Euclid's algorithm
divide, replace, repeat until remainder 0
Last divisor = HCF.
HCF result
the last non-zero divisor
Not the 0 remainder.
⚠️

Common mistakes & fixes

These are the exact errors that cost students marks in board exams. Read them once, save yourself the trouble.

WATCH OUT
Stopping Euclid's algorithm before the remainder is 0
Keep dividing until the remainder is 0; the last divisor is the HCF.
WATCH OUT
Taking the last remainder (0) as the HCF
The HCF is the last non-zero divisor, not the 0 remainder.
WATCH OUT
Ordering carelessly
Use a clear rule (size or alphabetical) and check each item.

Practice problems

Try each one yourself before tapping "Show solution". Active recall > rereading.

Q1EASY· Ordering
Arrange in ascending order: 34, 12, 27, 8.
Show solution
8, 12, 27, 34.
Q2MEDIUM· Euclid
Find the HCF of 48 and 18 using Euclid's algorithm.
Show solution
48 = 18×2 + 12; 18 = 12×1 + 6; 12 = 6×2 + 0 → HCF = 6.
Q3MEDIUM· Euclid
Find the HCF of 36 and 24 by Euclid's algorithm.
Show solution
36 = 24×1 + 12; 24 = 12×2 + 0 → HCF = 12.
Q4EASY· Concept
What is an iterative process?
Show solution
A process that repeats the same step again and again until a condition is met.
Q5EASY· Ordering
Sort alphabetically: Asha, Ravi, Bala, Kavi.
Show solution
Asha, Bala, Kavi, Ravi.
Q6MEDIUM· Euclid
Find the HCF of 60 and 48 by repeated division.
Show solution
60 = 48×1 + 12; 48 = 12×4 + 0 → HCF = 12.

5-minute revision

The whole chapter, distilled. Read this the night before the exam.

  • Term 3 Chapter 5 of Samacheer Kalvi Class 6 Maths.
  • Arranging in order makes information easy to find and compare.
  • An iterative process repeats the same step until a condition is met.
  • Euclid's division algorithm: divide, replace, repeat until the remainder is 0.
  • The HCF is the last non-zero divisor.
  • Euclid's game is an iterative number game that also leads to the HCF.

Tamil Nadu (TNBSE) marks blueprint

Where the marks come from in this chapter — so you can plan your prep.

Typical chapter weightage: 3-6 marks across ordering and algorithms

Question typeMarks eachTypical countWhat it tests
Ordering11-2Arranging numbers/names
Euclid's algorithm21-2HCF by repeated division
Concept11Iterative process
Prep strategy
  • Choose a clear ordering rule
  • Repeat division until remainder 0
  • Take the last non-zero divisor as HCF
  • Recognise repeating steps as iteration

Where this shows up in the real world

This chapter isn't just an exam topic — it lives in the world around you.

Searching

Ordered lists (dictionaries, directories) are quick to search.

Computing

Algorithms like Euclid's are used in programming.

Problem solving

Iterative steps solve many maths problems.

Exam strategy

Battle-tested tips from teachers and toppers for this chapter.

  1. State the ordering rule used
  2. Show each division step in Euclid's algorithm
  3. Report the last non-zero divisor as the HCF
  4. Identify the repeating step in iteration

Going beyond the textbook

For olympiad aspirants and curious learners — topics that build on this chapter.

  • Find the HCF of 1071 and 462 using Euclid's algorithm.
  • Explain how Euclid's game decides a winner.

Where else this chapter is tested

CBSE board isn't the only one — other exams test this chapter too.

TN Class 6 Term 3 ExamMedium
Logical Reasoning / OlympiadMedium
School unit testsHigh

Questions students ask

The real ones — pulled from the Q&A community and tutor sessions.

You divide the larger number by the smaller, then keep replacing the numbers with the divisor and remainder and dividing again, until the remainder is 0; the last divisor used is the HCF.

It repeats the same step over and over — each repetition is called an iteration — until some stopping condition is reached, like the remainder becoming 0.
Verified by the tuition.in editorial team
Last reviewed on 4 June 2026. Written and reviewed by subject-matter experts — read about our process.
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