Operations with Rational Numbers

This module focuses on how to perform basic math operations with rational numbers. Rational numbers include fractions, decimals, and integers that can be written as fractions. You'll learn specific steps for each operation to help you solve problems accurately.

Remember: Rational numbers are just fractions or numbers that can be written as fractions!

Adding & Subtracting Fractions

When adding or subtracting fractions, follow these steps:

1. Find the least common denominator (LCD) of the fractions. This is the smallest number that both denominators can divide into.

2. Convert each fraction to an equivalent fraction using the LCD.

3. Add or subtract the numerators (top numbers) while keeping the denominator the same.

4. Simplify your answer if possible by dividing both the numerator and denominator by their greatest common factor.

Pro Tip: Remember to follow the same adding and subtracting rules you learned for integers. If you're subtracting a negative fraction, it becomes addition!

Multiplying Fractions

Multiplying fractions is actually easier than adding them! Just follow these steps:

1. Multiply the numerators together to get your new numerator.

2. Multiply the denominators together to get your new denominator.

3. Simplify your answer by finding common factors that divide both the numerator and denominator.

Quick Trick: You can simplify before multiplying by crossing out common factors between numerators and denominators - this makes your calculations easier!

Dividing Fractions

Division with fractions uses a cool "Keep, Flip, Change" method:

1. Keep the first fraction exactly as it is.

2. Flip the second fraction (take its reciprocal) by switching the numerator and denominator.

3. Change the division symbol to a multiplication symbol.

4. Now multiply the fractions like you learned on the previous page and simplify your answer.

Remember: Division rules for integers still apply here. When dividing with negative numbers, remember that a negative divided by a negative equals a positive!

Adding & Subtracting Decimals

Working with decimals requires careful alignment:

1. Line up the decimal points vertically when writing your problem. This keeps place values properly aligned.

2. Add zeros as placeholders on the right side of shorter decimals if needed. For example, 0.5 becomes 0.50 if working with hundredths.

3. Perform the addition or subtraction from right to left, just like with whole numbers.

4. Bring down the decimal point to your answer directly below the decimal points in your problem.

Visual Help: Think of decimal place values like columns in a table - tenths, hundredths, thousandths must line up perfectly!