WAEC WAEC Nigeria General Mathematics

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(Positive and Negative Integers, Rational Numbers)

Rational Number Operations

Rational Number Operations

Understanding Rational Numbers

A rational number is any number that can be expressed as a fraction ab\frac{a}{b}, where aa and bb are integers, and b0b \neq 0.

Examples of rational numbers include:

  • 12\frac{1}{2}
  • 34-\frac{3}{4}
  • 55 (which can be written as 51\frac{5}{1})

Basic Operations with Rational Numbers

Addition and Subtraction

To add or subtract rational numbers, follow these steps:

  1. Find a common denominator: Make the denominators the same.
  2. Add or subtract the numerators: Keep the common denominator.
  3. Simplify the fraction: If possible, reduce the fraction to its simplest form.

Worked Example

Add 23+16\frac{2}{3} + \frac{1}{6}:

Multiplication

To multiply rational numbers:

  1. Multiply the numerators: Multiply the top numbers.
  2. Multiply the denominators: Multiply the bottom numbers.
  3. Simplify the fraction: Reduce the fraction if possible.

Worked Example

Multiply 23×45\frac{2}{3} \times \frac{4}{5}:

Division

To divide rational numbers:

  1. Flip the second fraction: Take the reciprocal of the divisor.
  2. Multiply: Follow the steps for multiplication.
  3. Simplify: Reduce if possible.

Worked Example

Divide 23÷45\frac{2}{3} \div \frac{4}{5}:

Tuity Tip

Hover me!

Tuity Tip: Always simplify your final answer to make it easier to understand and work with!

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