Class 4 — Mathematics
Data Handling: Bar Graphs and Tables
Class 4
- ✓By the end of this lesson students will be able to understand what data is.
- ✓By the end of this lesson students will be able to collect and record data in tables.
- ✓By the end of this lesson students will be able to read and interpret data from tables.
- ✓By the end of this lesson students will be able to understand what a bar graph is.
- ✓By the end of this lesson students will be able to read and interpret information presented in a bar graph.
Key concepts
Data means information or facts collected about something. For example, the number of students in your class, their favourite colours, or the number of trees in your garden are all examples of data. We collect data to understand things better.
A table is a way to organise data neatly in rows and columns. It helps us to see and understand the information quickly and clearly. Each row or column usually represents a different category or piece of information.
A bar graph is a chart that uses rectangular bars to show data. The length or height of each bar shows the quantity or number of items. Bar graphs make it easy to compare different pieces of data at a glance.
Every table and bar graph must have a title that tells us what the data is about. The labels on the sides or below the bars tell us what each row, column, or bar represents. Reading the title and labels is very important to understand the data correctly.
Key facts to remember
- 1Data is information or facts collected about something.
- 2Tables help us to organise data neatly in rows and columns.
- 3Bar graphs use rectangular bars to show data visually.
- 4The height or length of a bar in a bar graph shows the quantity or number.
- 5Always read the title and labels of a table or bar graph to understand the information correctly.
- 6Data handling helps us to understand and compare information easily.
Worked examples
Example 1
Some students were asked about their favourite colours. Here are their answers: Red, Blue, Green, Red, Yellow, Blue, Red, Green, Blue, Red. Organise this data in a table and answer the questions: (a) Which colour is liked by most students? (b) How many students like Green?
Answer
Table: Favourite Colours\n| Colour | Number of Students |\n|--------|--------------------|\n| Red | 4 |\n| Blue | 3 |\n| Green | 2 |\n| Yellow | 1 |\n(a) Red is liked by most students.\n(b) 2 students like Green.
Organising data in a table makes it very easy to find answers to questions.
Example 2
The bar graph below shows the number of storybooks read by four friends in a month. Read the bar graph and answer the questions: (a) Who read the most storybooks? (b) How many storybooks did Priya read? (c) Who read 3 storybooks?\n\n(Imagine a bar graph with the title 'Number of Storybooks Read'. The horizontal axis has names: Rahul, Priya, Amit, Seema. The vertical axis has numbers from 0 to 8, representing 'Number of Books'. The bars are: Rahul (6 books), Priya (4 books), Amit (8 books), Seema (3 books).)
Answer
(a) Amit read the most storybooks.\n(b) Priya read 4 storybooks.\n(c) Seema read 3 storybooks.
Always look at the height of the bar to find the quantity it represents.
Example 3
A teacher recorded the number of students present in Class 4 for five days of a week. The bar graph shows this data. (a) On which day were the most students present? (b) How many more students were present on Monday than on Friday? (c) What was the total number of students present on Tuesday and Wednesday?\n\n(Imagine a bar graph with the title 'Students Present in Class 4'. The horizontal axis has days: Monday, Tuesday, Wednesday, Thursday, Friday. The vertical axis has numbers from 0 to 40, representing 'Number of Students' in steps of 5. The bars are: Monday (35 students), Tuesday (30 students), Wednesday (30 students), Thursday (25 students), Friday (20 students).)
Answer
(a) Most students were present on Monday.\n(b) 15 more students were present on Monday than on Friday.\n(c) A total of 60 students were present on Tuesday and Wednesday.
For 'how many more' or 'how many less', we use subtraction. For 'total', we use addition.
Common mistakes
- ✗Not reading the title or labels of the table/graph carefully before answering questions.
- ✗Miscounting items when collecting data or making a table.
- ✗Confusing the quantities represented by different bars in a bar graph.
- ✗Not answering all parts of a question, especially when multiple questions are asked about one graph or table.
Exam tips
- ★Read the question carefully and understand what is being asked.
- ★Always look at the title and labels of tables and bar graphs first.
- ★Use a ruler or your finger to accurately read the height of bars in a bar graph.
- ★Double-check your calculations, especially when adding or subtracting numbers from the data.
Ready to practise?
Try a problem on this topic
Snap a photo or type a question — get step-by-step working instantly.