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FRACTIONS
CBSE · Class 6 · 🧮 Maths · Chapter 7

FRACTIONS

Fractional UnitsRepresenting Fractions on Number LineMixed FractionsEquivalent FractionsComparing FractionsAddition of Fractions

Chapter 7, 'Fractions', introduces students to the concept of fractions as parts of a whole and as equal shares. It covers identifying fractional units, representing fractions on a number line, understanding mixed fractions, and finding equivalent fractions. The chapter also delves into comparing, adding, and subtracting fractions, including Brahmagupta's method. Mastering fractions is crucial for advanced mathematical concepts and everyday problem-solving.

Fractional Units and Equal Shares

Jab ek poore unit ko equal parts mein divide karte hain, toh har part ko fractional unit ya unit fraction kehte hain.

  • Fractional Unit: Ek unit ka ek part jab us unit ko equal parts mein divide kiya gaya ho. Jaise, agar ek roti ko 2 equal parts mein divide kiya, toh har part \(\frac{1}{2}\) hai, jo ek fractional unit hai.
  • Example:
  • Ek apple ko 4 equal parts mein kaata, toh har part \(\frac{1}{4}\) hai.
  • Ek pizza ko 8 equal slices mein kaata, toh har slice \(\frac{1}{8}\) hai.

Key Idea: Fractions tab aate hain jab hum kisi cheez ko barabar hisson mein baantte hain. Har hissa ek fraction hota hai.

  • Numerator: Fraction ka upar wala number. Yeh batata hai ki kitne parts liye gaye hain.
  • Denominator: Fraction ka neeche wala number. Yeh batata hai ki poore unit ko kitne equal parts mein divide kiya gaya hai.

Example: \(\frac{3}{5}\) mein:

  • 3 hai Numerator (kitne parts liye)
  • 5 hai Denominator (total equal parts)

Important: Denominator kabhi bhi zero nahi ho sakta, kyunki hum kisi cheez ko zero equal parts mein divide nahi kar sakte.

📖Definition

Fraction: Ek number jo ek whole ke part ko represent karta hai. Isme ek numerator aur ek denominator hota hai, jo ek line se separate hote hain.

Remember

Hamesha yaad rakho, fractions mein parts equal hone chahiye. Agar parts equal nahi hain, toh woh fraction nahi kehlayega.

Fractional Units as Parts of a Whole

Fractions sirf ek unit ke parts hi nahi hote, balki woh ek collection ke parts bhi ho sakte hain.

  • Example: Ek box mein 10 chocolates hain. Agar aapne 3 chocolates kha li, toh aapne \(\frac{3}{10}\) chocolates kha li. Yahan, 10 chocolates ka collection ek 'whole' hai.

Visualizing Fractions:

  • Shape-based: Ek circle ko 4 equal parts mein divide kiya, 1 part shade kiya, toh woh \(\frac{1}{4}\) hai.
  • Collection-based: 5 balls mein se 2 red hain, toh red balls ka fraction \(\frac{2}{5}\) hai.

Different ways to divide a whole:

  • Ek chikki ko 6 equal parts mein kaatne ke kayi tareeke ho sakte hain (vertically, horizontally, diagonally), lekin har piece ka value \(\frac{1}{6}\) hi rahega. Shape matter nahi karta, equal division matter karta hai.

Types of Fractions (Basic):

  • Proper Fraction: Numerator denominator se chhota hota hai. Value 1 se kam hoti hai. Example: \(\frac{1}{2}, \frac{3}{4}, \frac{5}{8}\)
  • Improper Fraction: Numerator denominator se bada ya uske equal hota hai. Value 1 ya 1 se zyada hoti hai. Example: \(\frac{5}{3}, \frac{7}{4}, \frac{6}{6}\)
  • Unit Fraction: Numerator 1 hota hai. Example: \(\frac{1}{2}, \frac{1}{5}, \frac{1}{10}\)
Important

Har proper fraction ki value 1 se kam hoti hai, aur har improper fraction ki value 1 ya 1 se zyada hoti hai.

Measuring Using Fractional Units

Fractions ko hum lengths, weights, capacities, aur time jaise quantities ko measure karne ke liye use karte hain.

  • Example (Length): Agar ek paper strip 1 unit long hai. Agar hum usko 3 equal parts mein fold karein, toh har part \(\frac{1}{3}\) unit long hoga.
  • Addition of Fractional Units:
  • \(\frac{1}{4} + \frac{1}{4} = \frac{2}{4}\)
  • \(\frac{1}{5} + \frac{1}{5} + \frac{1}{5} = \frac{3}{5}\)
  • Jab denominators same hote hain, toh hum sirf numerators ko add karte hain.
  • Repeated Addition as Multiplication:
  • \(5 \text{ times } \frac{1}{4} = \frac{1}{4} + \frac{1}{4} + \frac{1}{4} + \frac{1}{4} + \frac{1}{4} = \frac{5}{4}\)
  • Iska matlab \(5 \times \frac{1}{4} = \frac{5}{4}\) bhi hota hai.

Practical Application:

  • Recipe mein ingredients ki quantity (\(\frac{1}{2}\) cup sugar).
  • Kapde ki length (\(\frac{3}{4}\) meter cloth).
  • Time duration (\(\frac{1}{4}\) hour = 15 minutes).
💡Tip

Fractions ko real-life situations se relate karna seekho. Word problems mein yeh bahut help karta hai.

Marking Fraction Lengths on the Number Line

Fractions ko number line par represent karna bahut important skill hai. Har fraction ka number line par ek unique point hota hai.

Steps to mark fractions on a number line:

  1. Ek number line draw karo.
  2. Whole numbers (0, 1, 2, 3...) ko mark karo.
  3. Jis fraction ko mark karna hai, uske denominator ko dekho.
  4. Har whole number ke beech ke space ko (jaise 0 aur 1 ke beech) denominator ke equal parts mein divide karo.
  5. Numerator ke according point mark karo.
  • Example: \(\frac{1}{2}\) ko mark karna hai.
  • 0 aur 1 ke beech ke space ko 2 equal parts mein divide karo.
  • Pehle part ke end par \(\frac{1}{2}\) mark karo.
  • Example: \(\frac{3}{4}\) ko mark karna hai.
  • 0 aur 1 ke beech ke space ko 4 equal parts mein divide karo.
  • Teesre part ke end par \(\frac{3}{4}\) mark karo.
  • Improper Fractions on Number Line: Improper fractions 1 ya 1 se bade hote hain. Jaise \(\frac{5}{3}\) ko mark karna hai.
  • \(\frac{5}{3}\) ko mixed fraction mein convert karo: \(1 \frac{2}{3}\).
  • Yeh fraction 1 aur 2 ke beech mein aayega.
  • 1 aur 2 ke beech ke space ko 3 equal parts mein divide karo.
  • Dusre part ke end par \(1 \frac{2}{3}\) ya \(\frac{5}{3}\) mark karo.

Important Observation:

  • 0 aur 1 ke beech mein infinite fractions hote hain. Aap jitne chaho utne parts mein divide kar sakte ho.
🚧Misconception

Students aksar 0 aur 1 ke beech ke parts ko galat count karte hain. Hamesha denominator ke according parts divide karo, aur numerator ke according point count karo.

Understanding Mixed Fractions

Mixed Fraction ya Mixed Number mein ek whole number part aur ek proper fraction part hota hai.

  • Example: \(2 \frac{1}{2}\) (do poore aur aadha).
  • 2 hai whole part.
  • \(\frac{1}{2}\) hai fractional part.

Conversion: Improper Fraction to Mixed Fraction

  1. Numerator ko denominator se divide karo.
  2. Quotient (भागफल) whole number part banega.
  3. Remainder (शेषफल) naya numerator banega.
  4. Denominator wahi rahega.
  • Formula: \(\text{Mixed Fraction} = \text{Quotient} \frac{\text{Remainder}}{\text{Divisor}}\)
  • Example: \(\frac{7}{3}\)
  • 7 ko 3 se divide kiya: \(7 \div 3 = 2\) (Quotient) aur \(1\) (Remainder).
  • Toh \(\frac{7}{3} = 2 \frac{1}{3}\).

Conversion: Mixed Fraction to Improper Fraction

  1. Whole number part ko denominator se multiply karo.
  2. Result mein numerator add karo.
  3. Yeh naya numerator banega.
  4. Denominator wahi rahega.
  • Formula: \(\text{Improper Fraction} = \frac{(\text{Whole Number} \times \text{Denominator}) + \text{Numerator}}{\text{Denominator}}\)
  • Example: \(2 \frac{1}{3}\)
  • \((2 \times 3) + 1 = 6 + 1 = 7\).
  • Toh \(2 \frac{1}{3} = \frac{7}{3}\).

Why convert? Calculations mein improper fractions zyada convenient hote hain, jabki mixed fractions real-life situations ko describe karne mein better hote hain.

💡Tip

Mixed aur improper fractions ke conversions par practice karna bahut zaroori hai. Yeh aksar exam mein direct questions ke roop mein aate hain.

Identifying Equivalent Fractions

Equivalent Fractions woh fractions hote hain jo same value ya same portion ko represent karte hain, bhale hi unke numerators aur denominators alag-alag hon.

  • Example: \(\frac{1}{2}, \frac{2}{4}, \frac{3}{6}, \frac{4}{8}\) sab equivalent fractions hain. Yeh sab aadhe ko represent karte hain.

How to find Equivalent Fractions:

  • Multiplication Method: Numerator aur Denominator dono ko same non-zero number se multiply karo.
  • Example: \(\frac{2}{3}\) ke equivalent fractions:
  • \(\frac{2 \times 2}{3 \times 2} = \frac{4}{6}\)
  • \(\frac{2 \times 3}{3 \times 3} = \frac{6}{9}\)
  • \(\frac{2 \times 5}{3 \times 5} = \frac{10}{15}\)
  • Division Method: Numerator aur Denominator dono ko unke common factor se divide karo.
  • Example: \(\frac{12}{18}\) ke equivalent fractions:
  • \(\frac{12 \div 2}{18 \div 2} = \frac{6}{9}\)
  • \(\frac{12 \div 3}{18 \div 3} = \frac{4}{6}\)
  • \(\frac{12 \div 6}{18 \div 6} = \frac{2}{3}\)

Lowest Terms (Simplest Form):

  • Ek fraction lowest terms mein hota hai jab uske numerator aur denominator ka common factor sirf 1 ho. Matlab, unhe aur divide nahi kiya ja sakta.
  • How to reduce to lowest terms: Numerator aur denominator ko unke HCF (Highest Common Factor) se divide karo.
  • Example: \(\frac{12}{18}\)
  • 12 aur 18 ka HCF 6 hai.
  • \(\frac{12 \div 6}{18 \div 6} = \frac{2}{3}\). \(\frac{2}{3}\) lowest terms mein hai.

Cross-Multiplication Test for Equivalence:

  • Do fractions \(\frac{a}{b}\) aur \(\frac{c}{d}\) equivalent honge agar \(a \times d = b \times c\) ho.
  • Example: \(\frac{2}{3}\) aur \(\frac{4}{6}\)
  • \(2 \times 6 = 12\)
  • \(3 \times 4 = 12\)
  • Kyunki \(12 = 12\), toh fractions equivalent hain.
Important

Equivalent fractions ka concept bahut important hai, especially jab hum fractions ko compare ya add/subtract karte hain. LCM (Least Common Multiple) ka use karke equivalent fractions banana aana chahiye.

Comparing Fractions

Fractions ko compare karne ka matlab hai yeh pata lagana ki kaunsa fraction bada hai, kaunsa chhota, ya kya woh equal hain.

Case 1: Same Denominators (Like Fractions)

  • Agar denominators same hain, toh jis fraction ka numerator bada hota hai, woh fraction bada hota hai.
  • Example: \(\frac{5}{7}\) aur \(\frac{3}{7}\). Yahan \(5 > 3\), toh \(\frac{5}{7} > \frac{3}{7}\).

Case 2: Same Numerators

  • Agar numerators same hain, toh jis fraction ka denominator chhota hota hai, woh fraction bada hota hai.
  • Example: \(\frac{3}{5}\) aur \(\frac{3}{8}\). Yahan \(5 < 8\), toh \(\frac{3}{5} > \frac{3}{8}\). (Socho, 3 roti ko 5 logon mein baantna vs 8 logon mein baantna).

Case 3: Different Numerators and Denominators (Unlike Fractions)

  • Yeh sabse common case hai. Isme hum fractions ko equivalent fractions mein convert karte hain jinka denominator same ho (LCM method).

Steps:

  1. Dono denominators ka LCM (Least Common Multiple) find karo.
  2. Har fraction ko uske equivalent fraction mein convert karo jiska denominator LCM ke equal ho.
  3. Ab, Case 1 ki tarah, numerators ko compare karo.
  • Example: \(\frac{2}{3}\) aur \(\frac{3}{4}\)
  1. 3 aur 4 ka LCM = 12.
  2. \(\frac{2}{3} = \frac{2 \times 4}{3 \times 4} = \frac{8}{12}\)
  3. \(\frac{3}{4} = \frac{3 \times 3}{4 \times 3} = \frac{9}{12}\)
  4. Ab \(\frac{8}{12}\) aur \(\frac{9}{12}\) ko compare karo. Kyunki \(8 < 9\), toh \(\frac{8}{12} < \frac{9}{12}\).
  5. Iska matlab \(\frac{2}{3} < \frac{3}{4}\).

Cross-Multiplication Method (Quick Check):

  • \(\frac{a}{b}\) aur \(\frac{c}{d}\) ko compare karne ke liye, \(a \times d\) aur \(b \times c\) ko compare karo.
  • Agar \(a \times d > b \times c\), toh \(\frac{a}{b} > \frac{c}{d}\).
  • Agar \(a \times d < b \times c\), toh \(\frac{a}{b} < \frac{c}{d}\).
  • Agar \(a \times d = b \times c\), toh \(\frac{a}{b} = \frac{c}{d}\).

Ascending/Descending Order:

  • Jab kayi fractions ko order karna ho, toh sabko same denominator wale equivalent fractions mein convert karke numerators ko compare karte hain.
💡Tip

Fractions ko compare karne ke liye LCM method sabse reliable hai, especially jab multiple fractions ko order karna ho. Cross-multiplication sirf do fractions ke liye quick check hai.

Addition and Subtraction of Fractions

Fractions ko add ya subtract karne ke liye, unke denominators same hone chahiye. Agar same nahi hain, toh unhe equivalent fractions mein convert karna padta hai.

Case 1: Same Denominators (Like Fractions)

  • Addition: Numerators ko add karo aur denominator wahi rakho.
  • Formula: \(\frac{a}{c} + \frac{b}{c} = \frac{a+b}{c}\)
  • Example: \(\frac{2}{7} + \frac{3}{7} = \frac{2+3}{7} = \frac{5}{7}\)
  • Subtraction: Numerators ko subtract karo aur denominator wahi rakho.
  • Formula: \(\frac{a}{c} - \frac{b}{c} = \frac{a-b}{c}\)
  • Example: \(\frac{5}{9} - \frac{2}{9} = \frac{5-2}{9} = \frac{3}{9}\)

Case 2: Different Denominators (Unlike Fractions) - Brahmagupta's Method

  • Steps:
  1. Dono denominators ka LCM find karo.
  2. Har fraction ko uske equivalent fraction mein convert karo jiska denominator LCM ke equal ho.
  3. Ab, Case 1 ki tarah, numerators ko add ya subtract karo.
  4. Final answer ko lowest terms mein reduce karo, agar possible ho.
  • Example (Addition): \(\frac{1}{2} + \frac{1}{3}\)
  1. 2 aur 3 ka LCM = 6.
  2. \(\frac{1}{2} = \frac{1 \times 3}{2 \times 3} = \frac{3}{6}\)
  3. \(\frac{1}{3} = \frac{1 \times 2}{3 \times 2} = \frac{2}{6}\)
  4. \(\frac{3}{6} + \frac{2}{6} = \frac{3+2}{6} = \frac{5}{6}\)
  • Example (Subtraction): \(\frac{3}{4} - \frac{1}{6}\)
  1. 4 aur 6 ka LCM = 12.
  2. \(\frac{3}{4} = \frac{3 \times 3}{4 \times 3} = \frac{9}{12}\)
  3. \(\frac{1}{6} = \frac{1 \times 2}{6 \times 2} = \frac{2}{12}\)
  4. \(\frac{9}{12} - \frac{2}{12} = \frac{9-2}{12} = \frac{7}{12}\)

Adding/Subtracting Mixed Fractions:

  • Method 1 (Convert to Improper): Mixed fractions ko pehle improper fractions mein convert karo, phir add/subtract karo. Final answer ko wapas mixed fraction mein convert kar sakte ho.
  • Method 2 (Separate Whole and Fractional Parts): Whole parts ko alag se add/subtract karo, aur fractional parts ko alag se add/subtract karo. Agar fractional part improper aaye, toh use mixed mein convert karke whole part mein add karo.
  • Example (Mixed Addition): \(2 \frac{1}{2} + 1 \frac{1}{3}\)
  • Method 1: \(\frac{5}{2} + \frac{4}{3} = \frac{15}{6} + \frac{8}{6} = \frac{23}{6} = 3 \frac{5}{6}\)
  • Method 2: \((2+1) + (\frac{1}{2} + \frac{1}{3}) = 3 + (\frac{3}{6} + \frac{2}{6}) = 3 + \frac{5}{6} = 3 \frac{5}{6}\)

Word Problems: Fractions ke addition/subtraction par based word problems bahut common hain. Carefully read karo ki kya add karna hai aur kya subtract.

🧮Formula

Brahmagupta's Method (General):

  1. Find LCM of denominators.
  2. Convert to equivalent fractions with LCM as denominator.
  3. Add/Subtract numerators, keep denominator same.
  4. Simplify to lowest terms.
🚧Misconception

Students aksar fractions ko add/subtract karte waqt denominators ko bhi add/subtract kar dete hain. Denominators same rehte hain, sirf numerators add/subtract hote hain.

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