Class 8 Maths Part 2 Chapter 5, Tales by Dots and Lines, deepens data handling: how the mean acts as a balance point, how outliers affect the mean and median, computing mean and median from frequency tables and spreadsheets, and reading line graphs and infographics.
What Class 8 Maths Chapter 5 Covers
5.1 The Balancing Act interprets the arithmetic mean as a centre of balance (where deviations on both sides cancel out), compares how adding, removing or shifting values changes the mean and median, and uses frequency tables and spreadsheets.
5.2 Visualising and Interpreting Data reads and plots time-series line graphs, multi-line graphs (including space debris, rainfall patterns and sleep data) and strip/infographic charts, ending with the Game of Hex.
Mean, median and spreadsheets: the mean is the sum of the values divided by their number, and the median is the middle value when the data is sorted. Adding the same constant to every value raises both by that constant; Sudhakar finds that shoes added 1 cm to every child’s measured height. The chapter teaches reading a spreadsheet, a grid of cells where a range such as D2:D6 holds the English marks of five students, and choosing between bar graphs and line graphs.
Exercises in Chapter 5
- Figure it Out exercise sets throughout the chapter with real-world applications and puzzles.
Read Class 8 Maths Chapter 5 Online
More Chapters
- Previous: Chapter 4: Exploring Some Geometric Themes
- Next: Chapter 6: Algebra Play
- All Maths chapters and the other Class 8 books: Class 8 NCERT books 2026-27
- All Class 1 to 12 NCERT Textbooks: NCERT Books PDF (Class 1–12)
- Every book chapter by chapter: NCERT chapter wise PDF
FAQ
How does adding a constant k to every data value affect the mean and median?
Both the mean and the median increase by that exact constant k.
When is a line graph preferred over a bar graph?
When tracking how a quantity changes continuously over time (such as temperature, rainfall across years, or growth).
What happens to the mean and median if every value increases by the same amount?
Both increase by that same amount.