Using Bar Graphs to Compare Quantities

Khan Academy

This video provides a clear, step-by-step tutorial on how to interpret data from a vertical bar graph to solve a comparison problem. The narrator demonstrates how to identify specific data points corresponding to different categories ('Bike World' and 'Bikes R Us') and determines the numerical value for each by reading the vertical axis. The content focuses on the key mathematical concept of finding the difference between two quantities. It explicitly models two distinct methods for solving the problem: first, by setting up a subtraction equation (19 - 12), and second, by visually counting the grid units on the graph to determine the 'gap' between the two bar heights. This dual approach reinforces the connection between arithmetic operations and visual data representation. This resource is excellent for early elementary classrooms introducing data analysis and graphing. It helps students transition from simply reading a graph to using the data to answer 'how many more' questions—a common hurdle for young learners. The video serves as a strong model for verifying answers, as it uses the visual counting method to check the arithmetic result.