Decimals & Fractions for Railway Group D - Notes, Tricks & Questions

Introduction

Decimals and fractions are fundamental topics in the Railway Group D Mathematics section. These concepts are essential for solving arithmetic problems, ratio & proportion, and data interpretation questions. Mastering decimals and fractions can significantly improve your calculation speed and accuracy in the exam.

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🔢 Understanding Decimals and Fractions

📌 What are Decimals?

A decimal number represents a fraction where the denominator is a power of 10. It is written with a decimal point (e.g., 0.5, 3.14, 2.75).

📌 Examples:

• 0.5 = 5/10
• 3.14 = 314/100
• 2.75 = 275/100

📌 What are Fractions?

A fraction represents a part of a whole and is written in the form a/b, where:

• "a" is the numerator (part of the whole).
• "b" is the denominator (total parts).

📌 Examples:

• 1/2 (One-half)
• 3/4 (Three-fourths)
• 5/8 (Five-eighths)

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📈 Conversion Between Decimals & Fractions

📌 Convert Fraction to Decimal:

• Divide the numerator by the denominator.
  • Example: 3/4 = 3 ÷ 4 = 0.75

📌 Convert Decimal to Fraction:

• Write the decimal as a fraction and simplify.
  • Example: 0.25 = 25/100 = 1/4

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💡 Short Tricks for Railway Exams

✔️ Converting Terminating Decimals to Fractions:

• Count decimal places and use powers of 10 as denominator.
  • Example: 0.6 = 6/10 = 3/5

✔️ Multiplication & Division of Decimals:

• Ignore the decimal, multiply/divide normally, and place the decimal in the answer.
  • Example: 1.5 × 2 = 3.0

✔️ Comparing Fractions Quickly:

• Convert fractions to decimals for easier comparison.
  • Example: Compare 3/5 and 2/3 → 3/5 = 0.6, 2/3 = 0.666 → 2/3 is greater.

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🔥 Practice Questions for RRB Group D Exam

🔹 Q1: Convert 0.375 into a fraction and simplify.
🔹 Q2: Multiply 2.4 × 1.5 using decimal rules.
🔹 Q3: Which is greater: 4/7 or 5/9?

📌 Comment your answers below!

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• Railway Group D Study Material
• Mathematics Tricks
• Competitive Exam Notes