Data Handling — Bar Graphs Notes & Questions | Class 4 Mathematics | Drishti OS

Data Handling — Bar Graphs

What you'll learn

Read a bar graph where the height (or length) of a bar shows a value.
Compare bars to find the greatest, smallest, and differences between categories.
Calculate totals from bar graph data.

Key concepts

Level 1 — What is a bar graph?

Verbal: A bar graph uses bars of different heights to show and compare data. Taller bars mean bigger values.

Level 2 — Reading a bar graph

Symbolic: If a bar for "Aarav" reaches the 15 mark and a bar for "Zara" reaches 20, Zara's value is 20 and Aarav's is 15.

Level 3 — Finding the greatest and smallest

Example: Bars showing 12, 18, 9, 25 → the tallest bar is 25, the shortest is 9.

Level 4 — Comparing and totalling

Example: Aarav = 15, Zara = 20. Difference = 20 − 15 = 5. Total of both = 15 + 20 = 35.

NCERT anchor: Math-Magic 4, Ch 14 — Smart Charts (reading and drawing pictographs and bar graphs).

Worked example

A bar graph shows books read: Kabir — 12, Meera — 18, Ishaan — 9, Diya — 21. Who read the most, and how many more books than Ishaan (who read the fewest)?

Step 1 — Compare all values: 12, 18, 9, 21. The greatest is 21 (Diya); the smallest is 9 (Ishaan).
Step 2 — Find the difference: 21 − 9 = 12.
Answer: Diya read the most (21 books), which is 12 more books than Ishaan.

Common mistakes

Mistake	Why it happens	Fix
Misreading the value where a bar ends	Not checking the scale/grid lines carefully	Trace across from the top of the bar to the value axis
Confusing "tallest" with "first in the list"	Not comparing all bars	Compare every value before deciding the greatest or smallest
Adding all bars when asked for a difference	Misreading the question	"How many more" means subtract; "total" means add
Forgetting units (books, goals, etc.)	Rushing the answer	Always restate the unit from the question in your answer

Quick check

Bars show 10, 25, 15. Which is the tallest? (25)
Aarav = 14, Zara = 22. How many more does Zara have? (8)
Four bars show 6, 9, 12, 13. What is the total? (40)
Bars show 30, 18, 30, 25. Is there a tie for the tallest? (Yes, two bars show 30)
Stretch: Bars show goals scored: Rohan — 7, Ananya — 11, Kabir — 4, Meera — 9. Find the total goals and how many more Ananya scored than Kabir. (Total = 31; 7 more)

Revision tip: Turn any pictograph you made at home into a bar graph by drawing bars whose heights match the pictograph values.

Open the Practice tab for graded questions on Bar Graphs.

Data Handling — Bar Graphs