Core Concept: Fractions represent parts of a whole. A fraction has two parts - numerator (top number) and denominator (bottom number). Decimals are another way to write fractions using place values after a decimal point. Both are extensively tested in SSC CGL. **
** Every fraction can be converted to decimal form by dividing numerator by denominator. Terminating decimals have denominators with only factors of 2 and 5. Non-terminating decimals have denominators with factors other than 2 and 5. When adding fractions, find common denominator first.
When multiplying fractions, multiply numerators together and denominators together. **
Decimal to Fraction: Remove decimal, divide by appropriate power of 10
SSC CGL frequently asks fraction comparisons, decimal conversions, arithmetic operations with mixed numbers, and word problems involving parts of quantities. Questions often involve finding equivalent fractions, simplifying complex fractions, and converting recurring decimals to fractions. Shortcut - Cross Multiplication for Comparison: To compare fractions a/b and c/d, multiply a×d and b×c. If a×d > b×c, then a/b > c/d. This saves time over finding common denominators.
Cross multiply - 7×6 = 42 and 9×5 = 45
Compare results - 42 < 45
Therefore 7/9 < 5/6 Converting Recurring Decimal 0.363636... to Fraction:
Let x = 0.363636...
Multiply by 100 (since 2 digits repeat): 100x = 36.363636...
Subtract original: 100x - x = 36
Solve: 99x = 36, so x = 36/99 = 4/11
Verify: 4÷11 = 0.363636... ✓ Another Shortcut - Decimal Place Memory: For quick conversions, remember that 1/8 = 0.125, 1/3 = 0.333..., 1/6 = 0.1666..., 1/7 = 0.142857... (repeating). These frequently appear in options. **
** Students often forget to simplify fractions to lowest terms or make errors with recurring decimals. Always reduce fractions by finding the highest common factor of numerator and denominator. Also, when dealing with mixed numbers, convert to improper fractions first before performing operations.
4graded MCQs · easy to hard · full solution & trap analysis