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Fractions & Mixed Numbers • Lesson 7 ⏱ 6 min read 📅 Updated Nov 2026

How to Add Fractions (With Like & Unlike Denominators)

Step-by-step guide to adding fractions with like and unlike denominators, including finding the LCD and simplifying final sums.

Interactive Visual Math Explorer Explore Pizza & Fractions

Slice the pizza or slide the fraction bar to observe how fractions, decimals, and percentages relate in real time:

Interactive Visual Explorer

Adding Fraction Slices

Try:
Golden Rule

NEVER add the denominators! The denominator tells you what kind of slice you have; the numerator counts how many slices you have.

1 / 4 1/4 1 of 4 Parts + 2 / 4 1/4 1/4 2 of 4 Parts = 3 / 4 1/4 1/4 1/4 3 of 4 Parts Total Rule: Like Denominators stay 4 unchanged! Add only the numerators: 1 + 2 = 3.
Fraction Addition Model: 1/4 + 2/4 = (1 + 2) / 4 = 3/4

Case 1: Like Denominators (Easy!)

Rule: Add Top, Keep Bottom

ad + bd = a + bd

Example: 15 + 25 = 1 + 25 = 35.

Case 2: Unlike Denominators (3 Simple Steps)

  1. Find LCD: For 2/3 + 1/4, the LCD is 12.
  2. Convert: 2 × 43 × 4 = 812 and 1 × 34 × 3 = 312.
  3. Add & Simplify: 8 + 312 = 1112.
Try It Yourself

Practice with Our Interactive Fraction Calculator

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Solved Step-by-Step Examples:1/3 + 1/42/5 + 3/10
Your Turn!

Check Your Understanding (3 Quick Questions)

Score: 0 / 3

Question 1: What is 2/7 + 3/7?

Question 2: Why is 1/4 + 2/4 NOT equal to 3/8?

Question 3: Calculate 1/2 + 1/3: