NCERT Class 8 Mathematics Mathematics: Chapter 13 — Introduction to Graphs
This chapter, "Introduction to Graphs," from NCERT Class 8 Mathematics, explains the importance of graphs in visually representing numerical data for quick understanding. It revisits line graphs, which display data changing continuously over time, using a "time-temperature graph" as an example. The chapter details how horizontal (x-axis) and vertical (y-axis) lines represent different variables, like time and temperature. It illustrates how to interpret trends and comparisons from these graphs, noting increases and decreases in data points. An example involving runs scored by two batsmen in different matches further demonstrates how to analyze and interpret line graphs to understand performance and consistency. This chapter equips students with essential data visualization skills crucial for mathematics and CBSE learning.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 8 |
| Subject | Mathematics |
| Book | Mathematics |
| Chapter | Chapter 13 — Introduction to Graphs |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 3 minutes |
| Word count | 452 |
Learning outcomes
- Understand the purpose and visual representation of data using graphs.
- Recall and identify line graphs and their components (x-axis, y-axis).
- Interpret data presented in line graphs to identify trends and make comparisons.
- Analyze performance data using graphical representations.
- Understand the difference between continuous and discrete data representation.
Vocabulary
| Word | Meaning |
|---|---|
| Graph | A visual representation of data. |
| Line graph | A graph that displays data that changes continuously over periods of time. |
| x-axis | The horizontal line representing one variable in a graph. |
| y-axis | The vertical line representing another variable in a graph. |
| Data | Numerical facts or information. |
| Visual representation | Showing information in a pictorial or graphical form. |
| Trend | A general direction in which something is developing or changing. |
| Comparison | The act or instance of comparing. |
The complete chapter text is read in the official NCERT PDF viewer below (streamed from ncert.nic.in). This page provides NCERT Help study material — summary, vocabulary, practice questions, and FAQs — not a full reproduction of the textbook.
Read chapter online
This PDF is loaded from the official NCERT website (ncert.nic.in). Use the page buttons below to read — download is disabled on NCERT Help.
Read page by page below. PDF is streamed from the official NCERT website — no download button on this page.
Practice questions
- What is the main purpose of a graph? Answer: To show numerical facts in visual form so that they can be understood quickly, easily, and clearly.
- What type of graph displays data that changes continuously over periods of time? Answer: A line graph.
- In a time-temperature graph, what does the horizontal line (x-axis) usually represent? Answer: The timings at which the temperatures were recorded.
- What does the vertical line (y-axis) usually represent in a graph? Answer: It represents the variable being measured, such as temperature or runs scored.
- According to Fig 13.1 and 13.2, what was the temperature at 10 a.m.? Answer: The temperature was 40°C.
Frequently asked questions
What is a graph?
A graph is a visual representation of data, used to understand numerical facts quickly and clearly.
What is a line graph used for?
A line graph is used to display data that changes continuously over periods of time.
What do the axes on a graph represent?
The horizontal line is the x-axis, and the vertical line is the y-axis. They represent different variables being measured or compared.
How can a graph help in understanding data?
Graphs make data easier to understand, especially for showing trends and making comparisons, by presenting it visually.
Can graphs show information not explicitly recorded?
Yes, a line graph can suggest values between recorded points, implying trends or intermediate states.
What information is shown on the x-axis in Fig 13.3?
The x-axis in Fig 13.3 shows the matches played during the year 2007.
What information is shown on the y-axis in Fig 13.3?
The y-axis in Fig 13.3 shows the total runs scored in each match.
Related resources
Important topics
Topics covered
NCERT Class 8 Mathematics — Mathematics — Chapter 13 — Introduction to Graphs. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.