Rational numbers

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A rational number is a number that can be written as the ratio of two integers.

Rational numbers

The difference between rational numbers and fractions lies in the fact that fractions cannot have a negative numerator or denominator.

Examples of rational numbers:

  • $\frac{4}{5} , \frac{-2}{-6} , \frac{-10}{5}$, etc.
  • Zero is a rational number that can be expressed as a fraction with a non-zero denominator: $\frac{0}{20} , \frac{0}{-15}$, etc.
  • Every natural number: $1 = \frac{1}{1}$
  • Every fraction (the numerator and denominator are whole numbers and the denominator is not equal to zero): $\frac{18}{7} , \frac{3}{5}$, etc.
  • Positive rational numbers (numerator and denominator have the same signs (either both positive or both negative): $\frac{7}{12} , \frac{-18}{-7}$, etc.
  • Negative rational numbers (numerator and denominator have different signs): $\frac{-7}{12} , \frac{18}{-7}$, etc.
  • Decimals (as they can be written as fractions with denominators 10, 100, 1000…): 0.45, 0.5446, 0.01864, etc.