Quantitative Aptitude - Decimal Fraction - Formula & Concept Tutorial

1. Decimal Fraction

Its is a fractions in which denominators are power of 10.

For example –

2. Conversion of decimal into fraction

To convert decimal into fraction, find the decimal place of number.

Suppose in 0.005 decimal place is at 1000 place (10³) . Then multiply and divide the number 0.005 with 10³. Then the final result will be in fraction.

For example -

3. Some Basic Formulae:

• (a + b)² + (a – b)² = 2(a² + b²⁾
• (a + b)² - (a – b)² = 4ab
• (a² – b²) = (a – b)(a + b)
• (a + b)² = (a² + b² + 2ab)
• (a – b)² = (a² + b² – 2ab)
• (a + b + c)² = a² + b² + c² + 2(ab + bc + ca)
• (a + b)³ = (a³ + b³ + 3ab(a+b))
• (a³ + b³) = (a + b)(a² – ab + b²)
• (a³ – b³) = (a – b)(a² + ab + b²)
• (a³ + b³ + c³ – 3abc) = (a + b + c)(a² + b² + c² – ab – bc – ac)
• When a + b + c = 0, then a³ + b³ + c³ = 3abc.