Schooling · Class 6 · Mathematics · Data Handling and Presentation · Chapter on a page
CBSE Class 6 · Mathematics · NCERT Ganita Prakash
Data Handling and Presentation: chapter on a page
A cut of Shishya's notes for this chapter: the first paragraph of the introduction and the key ideas, formulas and facts, common mistakes and quick revision lists, word for word. Nothing is added or reworded; the worked examples are left out (they are on the chapter page).
About the notes: Written by Shishya's AI on 26 Sept 2026 from the chapter's title and class level, in Shishya's own words — not a copy or summary of the textbook. Read the official chapter for the book's own text, activities and exercises.
Fact-checked on 21 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain.
Mind map
Drawn from the same notes by a fixed rule (no AI): each label is the item's own words — its bold term, its label before a colon, a short formula as written, or its first words.
The mind map as a list
- Key ideas
- Data
- Tally marks
- frequency
- frequency table
- pictograph
- bar graph
- Choosing a suitable scale is important
- Formulas and facts
- Tally mark groups
- Frequency = count of how many times…
- In a pictograph, total for a…
- In a bar graph, all bars must have…
- The scale on the vertical axis must…
- Watch out for
- Forgetting to cross every fifth…
- Making bars of different widths
- Ignoring the key in a pictograph
- Using unequal gaps on the scale
- Adding frequencies that do not match…
What this chapter is about
Every day we meet numbers that tell us something useful. How many students were absent this week? Which fruit is most popular in your class? How much rain fell each month during the monsoon? These numbers are called data — pieces of information we collect to answer a question.
Key ideas
- Data means facts or numbers collected to answer a question. Example: the heights of all students in your class.
- Tally marks are short strokes used to count items quickly. Every fifth mark crosses the first four, making groups of five that are easy to add.
- A frequency is the number of times a particular item or value appears in your data.
- A frequency table lists each item along with its frequency, helping you see totals at a glance.
- A pictograph uses small pictures or symbols to show data. A key tells you what one picture stands for (for example, one ball picture = 5 runs).
- A bar graph uses rectangular bars of equal width. The height of each bar shows the frequency or value it represents.
- Choosing a suitable scale is important: if one symbol stands for too few items, your pictograph becomes crowded; if it stands for too many, you cannot show small differences.
- Graphs make it easy to compare groups and spot the highest, lowest or most common item quickly.
Formulas and facts to remember
- Tally mark groups: |||| with a slanted stroke through them equals 5.
- Frequency = count of how many times an item appears.
- In a pictograph, total for a category = number of symbols × value of one symbol.
- In a bar graph, all bars must have the same width and start from a common base line.
- The scale on the vertical axis must have equal gaps (for example, 0, 10, 20, 30…).
Common mistakes
- Forgetting to cross every fifth tally mark → always bundle tallies in fives to avoid counting errors.
- Making bars of different widths → keep all bars equally wide; only the height should change.
- Ignoring the key in a pictograph → always check what one symbol stands for before calculating.
- Using unequal gaps on the scale → the axis must go up by the same amount each step (5, 10, 15… not 5, 10, 20).
- Adding frequencies that do not match the total data count → always verify your sum equals the number of items you collected.
Quick revision
- Data is information collected to answer a question.
- Tally marks help you count quickly; every fifth mark crosses the first four.
- A frequency table shows each item and how often it appears.
- A pictograph uses symbols; multiply the number of symbols by the key value.
- A bar graph uses bars of equal width; height shows frequency.
- Always label your graph and include a title.