Bar models are visual tools used in mathematics to represent numbers and their relationships. They consist of rectangular bars that can be divided into parts, making it easier to understand concepts like addition, subtraction, multiplication, and division. By using bar models, students can visualize problems and see how different quantities relate to one another. These models are particularly helpful in teaching fractions, ratios, and proportions. They allow learners to break down complex problems into simpler, more manageable parts. Bar models can be used in various educational settings, helping students develop a deeper understanding of mathematical concepts through visual representation.