This personal site explains how to add fractions with different denominators by finding the least common denominator. Gives problems and games to practice this skill.

This site describes how to add fractions with like denominators. It provides exercises and games to practice the skill.

This tutorial focuses on basic subtraction, subtraction facts, subtraction skills, subtraction of fractions and subtraction of positive and negative integers. Features include practice exercises and games.

This site explains how to add mixed numbers that have the same denominator, and includes games to practice this skill.