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Class 6 Mathematics Chapter 7 Fractions — Formulas & Key Points

CBSE Class 6 Mathematics Chapter 7 introduces fractions as parts of a whole, building on concepts students learned in earlier classes. This formula sheet consolidates all key definitions, operations and comparison methods from the NCERT textbook. Whether you are solving homework problems or preparing for periodic tests, this page gives you every formula and rule you need at your fingertips, organized for quick reference and last-minute revision.

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Key takeaways

  • Equivalent fractions are obtained by multiplying or dividing both numerator and denominator by the same non-zero number.
  • To compare unlike fractions, convert them to like fractions by finding the LCM of denominators.
  • When adding or subtracting fractions, denominators must be the same; only numerators are added or subtracted.
  • To multiply fractions, multiply numerators together and denominators together, then simplify.
  • Division of fractions is done by multiplying the first fraction by the reciprocal of the second fraction.
  • A fraction is in simplest form when the HCF of numerator and denominator is 1.
  • Every fraction can be represented as a point on the number line between two whole numbers.

Core Definitions and Key Terms

Understanding the vocabulary of fractions is the foundation of Chapter 7. A fraction represents a part of a whole and is written as numerator over denominator. The numerator tells how many parts we have, while the denominator tells how many equal parts the whole is divided into. Proper fractions have numerator smaller than denominator, improper fractions have numerator greater than or equal to denominator, and mixed numbers combine a whole number with a proper fraction. Like fractions share the same denominator, making them easy to compare and operate on. Unlike fractions have different denominators and require conversion before addition or subtraction. An equivalent fraction represents the same value but has different numerator and denominator. A fraction is in its simplest or lowest form when the HCF of numerator and denominator is 1.
  • Fraction: A number representing part of a whole, written as p/q where q ≠ 0
  • Numerator: The top number in a fraction, showing how many parts are taken
  • Denominator: The bottom number, showing total equal parts in the whole
  • Proper fraction: Numerator < Denominator (e.g. 3/5, 7/12)
  • Improper fraction: Numerator ≥ Denominator (e.g. 7/5, 9/9)
  • Mixed number: A whole number combined with a proper fraction (e.g. 2 1/3)
  • Like fractions: Fractions with the same denominator (e.g. 2/7, 5/7, 6/7)
  • Unlike fractions: Fractions with different denominators (e.g. 1/2, 3/5, 7/8)
  • Unit fraction: Fraction with numerator 1 (e.g. 1/2, 1/5, 1/10)

Essential Formulas for Fraction Operations

This table presents every formula you need for CBSE Class 6 Mathematics Chapter 7. Each operation has a specific rule that must be followed. Memorize the conversion between improper fractions and mixed numbers, as both forms appear in NCERT exercises. The simplification formula using HCF is crucial for presenting answers in the form teachers expect. When working with word problems, identifying which operation to use is half the battle — addition for combining parts, subtraction for finding difference, multiplication for finding part of a part, and division for sharing or grouping problems.

Comparing and Ordering Fractions

Comparing fractions is a vital skill tested in CBSE examinations. When fractions have the same denominator (like fractions), simply compare numerators — the fraction with the larger numerator is greater. When denominators are the same and numerators differ, comparison is straightforward. However, most real-world problems and NCERT exercises involve unlike fractions. The standard method is to convert all fractions to like fractions by finding the Least Common Multiple (LCM) of all denominators, then rewriting each fraction with this common denominator. After conversion, compare the new numerators. For fractions with the same numerator, the one with the smaller denominator is larger because each part is bigger. Cross-multiplication is a quick method for comparing two fractions: for a/b and c/d, compute a×d and b×c, then compare these products. This method works well for two fractions but becomes cumbersome for three or more.
  • Like fractions: Compare numerators directly; larger numerator means larger fraction
  • Unlike fractions: Find LCM of denominators, convert to like fractions, then compare
  • Same numerator: Fraction with smaller denominator is greater (1/3 > 1/5)
  • Cross-multiplication for two fractions a/b and c/d: if a×d > b×c, then a/b > c/d
  • Ordering: Arrange fractions in ascending (smallest to largest) or descending (largest to smallest) order
  • Unit fractions: Among 1/2, 1/3, 1/5, 1/7, the one with smallest denominator is largest

Fractions on the Number Line

Representing fractions on a number line helps visualize their position and understand their magnitude relative to whole numbers and other fractions. Every fraction corresponds to a unique point on the number line. Proper fractions lie between 0 and 1, while improper fractions or mixed numbers lie beyond 1. To plot a fraction p/q, divide the segment between two consecutive whole numbers into q equal parts, then count p parts from the starting whole number. For example, to plot 3/5, divide the segment from 0 to 1 into 5 equal parts and mark the third division point. For mixed numbers like 2 3/4, start at whole number 2, divide the segment from 2 to 3 into 4 equal parts, and mark the third point. This visual method reinforces understanding of fraction size, helps with comparison, and makes addition and subtraction more intuitive. NCERT Class 6 Mathematics emphasizes number line representation in multiple exercises to build spatial understanding of fractions.
  • Proper fractions appear between 0 and 1 on the number line
  • Improper fractions and mixed numbers appear beyond 1
  • To plot p/q: divide unit segment into q equal parts, count p parts
  • Fractions to the right are greater than fractions to the left
  • Equal fractions occupy the same point (e.g. 1/2, 2/4, 3/6 are at the same location)
  • Number line helps visualize addition: start at first fraction, move right by second fraction

Step-by-Step: Adding and Subtracting Fractions

Addition and subtraction of fractions follow clear rules based on whether denominators match. For like fractions (same denominator), the process is simple: keep the denominator unchanged and add or subtract only the numerators. This mirrors combining similar objects. For unlike fractions, you must first find a common denominator, typically the LCM of the original denominators, to ensure you are adding or subtracting comparable parts. Convert each fraction to an equivalent fraction with this common denominator, then perform the operation on numerators. Always simplify the result by dividing numerator and denominator by their HCF. Mixed numbers require conversion to improper fractions before addition or subtraction, then convert the final answer back to mixed form if needed. CBSE Class 6 Mathematics solutions frequently test this multi-step process, so practice is essential.
  • Like fractions: Add or subtract numerators, keep denominator same (2/7 + 3/7 = 5/7)
  • Unlike fractions: Find LCM of denominators, convert to like fractions, then operate
  • Always simplify final answer to lowest terms using HCF
  • For mixed numbers: convert to improper fractions first, operate, convert back if required
  • Check: result should make logical sense (adding two fractions less than 1 should not exceed 2)

Multiplying and Dividing Fractions

Multiplication of fractions is the most straightforward operation: multiply the numerators to get the new numerator, multiply the denominators to get the new denominator, then simplify. There is no need to find a common denominator. This operation answers questions like 'what is half of one-third' or 'find two-fifths of fifteen'. You can simplify before multiplying by canceling common factors between any numerator and any denominator — this makes calculation easier and reduces the final simplification step. Division of fractions uses the reciprocal method: to divide by a fraction, multiply by its reciprocal (flip numerator and denominator). So a/b ÷ c/d becomes a/b × d/c. This transforms every division problem into a multiplication problem. Remember the phrase 'invert and multiply' or 'keep-change-flip': keep the first fraction, change division to multiplication, flip the second fraction. After multiplying, simplify the result. Division by zero is undefined, so c/d must not be zero (meaning c≠0). NCERT Class 6 Mathematics devotes several exercises to mastering these operations because they form the basis for algebra and higher mathematics.
  • Multiplication: (a/b) × (c/d) = (a×c)/(b×d), then simplify
  • Simplify before multiplying by canceling common factors diagonally
  • Division: (a/b) ÷ (c/d) = (a/b) × (d/c) — multiply by reciprocal
  • Reciprocal of a/b is b/a; reciprocal of whole number n is 1/n
  • Multiplying by a proper fraction makes the result smaller
  • Dividing by a proper fraction makes the result larger
  • Never divide by zero; c in c/d must not be zero

Common Mistakes and How to Avoid Them

CBSE Class 6 Mathematics Chapter 7 has predictable error patterns that cost students marks in exams. The most frequent mistake is adding or subtracting unlike fractions by operating on both numerators and denominators separately (e.g. wrongly computing 1/2 + 1/3 as 2/5). Always convert to like fractions first. Another common error is forgetting to simplify the final answer — teachers deduct marks if you write 6/8 instead of 3/4. When multiplying mixed numbers, students often forget to convert them to improper fractions first, leading to wrong results. In division problems, some children invert the wrong fraction; remember to flip only the divisor (the second fraction), not the dividend. Notation errors include writing the division symbol incorrectly or omitting the fraction bar. Comparing fractions without finding common denominator or incorrectly applying cross-multiplication are frequent comparison mistakes. Always double-check which fraction you are converting and ensure the HCF you use for simplification is truly the highest common factor, not just any common factor.
  • Never add/subtract unlike fractions without converting to common denominator first
  • Always present final answer in simplest form by dividing by HCF of numerator and denominator
  • Convert mixed numbers to improper fractions before multiplying or dividing
  • In division, invert only the second fraction (divisor), not the first (dividend)
  • When finding LCM for comparison, ensure you take LCM of denominators, not numerators
  • Do not cancel terms across addition or subtraction, only across multiplication/division
  • Check that denominators match before adding/subtracting numerators
  • Ensure you write the fraction bar clearly; sloppy notation leads to confusion

Memory Tricks and Mnemonics for Fractions

Memory aids make fraction operations easier to recall under exam pressure. For division, remember 'KCF' — Keep the first fraction, Change division to multiplication, Flip the second fraction. When comparing fractions, think 'LCD' (Lowest Common Denominator) to remind you to find LCM of denominators. To recall which operation keeps denominators the same, remember 'Add/Subtract: Same House' — addition and subtraction require fractions to live in the same house (same denominator). For equivalent fractions, use 'Multiply or Divide Together' — whatever you do to the top, do to the bottom by the same number. The phrase 'Top times Top, Bottom times Bottom' helps with multiplication. To remember that smaller denominator means bigger unit fraction, visualize pizza slices: cutting a pizza into 3 pieces gives bigger slices than cutting into 8 pieces, so 1/3 > 1/8. For simplification, think 'HCF makes it Simple' — find the Highest Common Factor to reduce to simplest form. These tricks, combined with regular practice on CBSETUTOR.ai, help students retain concepts long-term.
  • Division: KCF = Keep, Change, Flip (keep first, change ÷ to ×, flip second)
  • Comparison: LCD = Lowest Common Denominator (find LCM of denominators)
  • Addition/Subtraction: 'Same House' = same denominator required
  • Equivalent fractions: 'Do the Same to Top and Bottom'
  • Multiplication: 'Top×Top, Bottom×Bottom'
  • Unit fractions: 'Smaller Denominator = Bigger Slice'
  • Simplification: 'HCF makes it Simple'
  • Mixed to improper: 'Multiply whole by bottom, add top, keep bottom'

Three Solved Mini-Examples Applying Formulas

Worked examples cement understanding by showing exactly how formulas are applied in NCERT-style problems. These three examples cover the most frequently tested concepts in CBSE Class 6 Mathematics Chapter 7 — finding equivalent fractions, adding unlike fractions, and multiplying a whole number by a fraction. Each solution follows the step-by-step method taught in the NCERT textbook, showing all working clearly. Students should practice similar problems from their Class 6 Mathematics solutions and verify answers. Regular practice on CBSETUTOR.ai provides instant feedback with photo-upload solving for every NCERT exercise at just ₹999 per month across all subjects and classes 6 to 12, with a 3-day free trial for new users.

Decimal Representation of Fractions

Chapter 7 introduces the connection between fractions and decimals, a foundational link for higher mathematics. Any fraction can be converted to a decimal by dividing the numerator by the denominator. Some fractions yield terminating decimals (e.g. 1/2=0.5, 3/4=0.75, 7/20=0.35), while others produce recurring or non-terminating decimals (e.g. 1/3=0.333..., 2/7=0.285714285714...). Fractions with denominators that are powers of 10 (10, 100, 1000) convert directly to decimals: 7/10=0.7, 23/100=0.23, 456/1000=0.456. Conversely, decimals can be written as fractions: write the decimal without the point as numerator, and the appropriate power of 10 as denominator, then simplify. For example, 0.8 = 8/10 = 4/5. Understanding this two-way conversion is essential for problem-solving and real-world applications like money and measurements. NCERT Class 6 Mathematics notes emphasize practice in both directions to build fluency.
  • To convert fraction to decimal: divide numerator by denominator
  • Terminating decimals end after a finite number of digits (1/4 = 0.25)
  • Recurring decimals repeat indefinitely (1/3 = 0.333...)
  • Fractions with denominator 10, 100, 1000 give easy decimals (17/100 = 0.17)
  • To convert decimal to fraction: write digits over appropriate power of 10, then simplify
  • 0.5 = 5/10 = 1/2, 0.25 = 25/100 = 1/4, 0.75 = 75/100 = 3/4

Last-Minute Revision Box — One-Glance Summary

This quick-reference box consolidates the entire chapter into bullet points for revision the night before your exam or during the morning bus ride to school. Keep this section bookmarked on your phone for instant access. Pair it with daily practice on CBSETUTOR.ai where you can upload photos of tricky NCERT problems and get step-by-step solutions instantly, available 24×7 at a flat fee of ₹999 per month covering all subjects for classes 6 to 12, with a risk-free 3-day trial.
  • Fraction = numerator/denominator; denominator ≠ 0
  • Like fractions: same denominator; Unlike fractions: different denominators
  • Equivalent fraction: multiply/divide top and bottom by same non-zero number
  • Simplest form: HCF(numerator, denominator) = 1
  • Improper to mixed: divide numerator by denominator, write quotient (remainder/denominator)
  • Mixed to improper: (whole×denominator + numerator)/denominator
  • Compare unlike fractions: convert to like fractions using LCM of denominators
  • Addition/subtraction of like fractions: (a±b)/c, keep denominator same
  • Addition/subtraction of unlike fractions: find LCM, convert, then add/subtract numerators
  • Multiplication: (a/b)×(c/d) = (a×c)/(b×d), simplify by canceling before or after
  • Division: (a/b)÷(c/d) = (a/b)×(d/c) — invert second, then multiply
  • Fraction to decimal: numerator ÷ denominator
  • Decimal to fraction: write over power of 10, simplify
  • Number line: proper fractions between 0 and 1, improper beyond 1
  • Always simplify final answer; never leave 4/6, write 2/3

Frequently asked questions

What is the difference between like and unlike fractions?+
Like fractions have the same denominator, such as 2/9, 5/9 and 7/9. Unlike fractions have different denominators, like 1/2, 3/5 and 7/8. Like fractions can be directly added or subtracted, while unlike fractions must first be converted to a common denominator.
How do I find equivalent fractions for any given fraction?+
Multiply or divide both the numerator and denominator by the same non-zero number. For example, 2/3 = (2×2)/(3×2) = 4/6, or 2/3 = (2×5)/(3×5) = 10/15. Infinite equivalent fractions exist for any fraction.
Why must fractions have a common denominator before adding or subtracting?+
Denominators represent the size of parts. You can only combine parts of the same size. Adding 1/4 and 1/3 directly would mix quarter-pieces with third-pieces, which is mathematically incorrect. Converting to 3/12 + 4/12 ensures all parts are twelfth-sized, making addition valid.
What is the easiest way to compare two fractions with different denominators?+
For two fractions, cross-multiplication is quick: for a/b and c/d, calculate a×d and b×c. If a×d > b×c, then a/b > c/d. For three or more fractions, find the LCM of denominators and convert all to like fractions, then compare numerators.
How do I remember the rule for dividing fractions?+
Use the mnemonic 'Keep-Change-Flip' or KCF. Keep the first fraction as it is, change the division sign to multiplication, and flip (find the reciprocal of) the second fraction. Then multiply the two fractions and simplify the result.
When should I convert a mixed number to an improper fraction?+
Always convert mixed numbers to improper fractions before multiplying or dividing. For addition and subtraction, you can work with mixed numbers directly or convert them — converting often makes the process clearer and reduces mistakes.
What does it mean to simplify a fraction to its lowest terms?+
Simplifying means dividing both numerator and denominator by their Highest Common Factor (HCF) until no common factor other than 1 remains. For example, 8/12 simplified is 2/3 because HCF(8,12)=4, and 8÷4=2, 12÷4=3.
Can every fraction be represented as a decimal?+
Yes, every fraction can be written as a decimal by dividing the numerator by the denominator. Some fractions give terminating decimals like 1/4=0.25, while others give non-terminating repeating decimals like 1/3=0.333... Both are valid decimal representations.
How do I plot a fraction like 5/3 on a number line?+
5/3 is an improper fraction equal to 1 2/3. Locate 1 and 2 on the number line. Divide the segment between 1 and 2 into 3 equal parts. Starting from 1, count 2 parts to the right. That point represents 5/3 or 1 2/3.
Where can I get instant help with NCERT Class 6 Mathematics Chapter 7 Fractions problems?+
CBSETUTOR.ai offers 24×7 AI-powered tutoring where you can upload photos of any NCERT fraction problem and receive step-by-step solutions instantly. At ₹999 per month for all subjects and classes 6–12, with a 3-day free trial, it is an affordable way to strengthen your fraction concepts and score better in exams.

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