Rational Numbers, Revision Notes: ICSE Class 8 MATHS, Mathematics

Rational Numbers

The numbers, which can be written in the form $\frac{p}{q}$ , where p and q are integers and q ≠ 0, are called rational numbers. Rational numbers can be positive as well as negative. Rational numbers include all integers and fractions.

For example

$- \frac{2}{7}, \frac{41}{366}, 2 = \frac{2}{1}, etc.$

All the operations on rational numbers are performed as in fractions.

Example: Solve

Solution:

$= \frac{- 3 \times 3 + 5 \times 2}{12} = \frac{- 9 + 10}{12} = \frac{1}{12}$

$= \frac{2 \times 5 - 3 \times 7}{35} = \frac{10 - 21}{35} = - \frac{11}{35}$

When 0 is added to any rational number, say $\frac{p}{q}$ , the same rational number is obtained. Therefore, 0 is the additive identity of rational numbers.

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