Chapter 10: Fun at Class Party!

The class is planning a party. Who likes samosa? Who likes idli? Who wants juice? With so many friends to count, we need a smart way to keep track. Welcome to data handling!

What we'll learn

• Collect simple information from friends.
• Use tally marks to count.
• Read and draw pictographs.
• Make easy bar graphs.
• Answer questions from a picture chart.

The big idea

When we ask a question to many people, we get information. Information that is organised neatly is called data. Asking "What is your favourite fruit?" to 25 classmates gives us data about fruits.

Tally marks make counting easy. Each mark is a single line. The fifth one crosses the first four , like a gate. So |||| with a slash means 5. Counting tally marks in groups of 5 is very fast.

A pictograph uses pictures to show numbers. One small mango picture might mean one mango. If 6 children like mangoes, we draw 6 mango pictures in that row. A glance tells us which fruit wins.

A bar graph uses tall and short bars. The taller the bar, the bigger the number. Bars make comparison easy , we can see at once who is on top.

Let's explore

Favourite snack. Ask 10 family or class friends , samosa, vada or idli? Make tally marks for each. Who wins?

Pictograph of pets. Make a pictograph of pets owned by your friends , dog, cat, parrot, fish. Use one small picture per pet.

Colour count. Look at your pencil box. Count how many pencils of each colour. Draw bars in your notebook.

Birthday months. Ask 5 friends in which month they were born. Note them down. Which month has the most birthdays?

Worked examples

Example 1. A class voted for favourite drinks: juice 7, milk 4, water 5, lassi 9. Which is most liked?

• Compare: 9 > 7 > 5 > 4.
• Lassi got the most votes.

Example 2. Show 12 using tally marks.

• Two groups of 5 = ||||/ ||||/.
• One group of 2 = ||.
• Total: ||||/ ||||/ ||.

Example 3. In a pictograph, 1 ball means 1 child. The cricket row has 8 balls. The football row has 5 balls. How many more children like cricket?

• 8 − 5 = 3.
• 3 more children like cricket.

Quick check

1. How would you write the number 7 using tally marks?
2. In a pictograph, why is it useful to show pictures of equal size?
3. Make tally marks for: 4, 9, 13.
4. Bar graph: rose 6, lily 3, marigold 8. Which flower has the tallest bar?
5. Why do we need to organise data?

Recap

• Data is information we collect by asking or observing.
• Tally marks help us count in fives.
• Pictographs and bar graphs make data easy to see.