📊 Chapter 12 – Smart Charts
Subject: Mathematics
Main Concepts: Tally Marks, Tables, Bar Charts, Pie Charts, Growth Charts
📘 Introduction
In our daily life, we collect a lot of information such as favourite animals, vehicles on roads, temperature, or growth of plants. To understand this information easily, we use charts and graphs.
- Organise data
- Compare numbers easily
- Understand patterns
🐶 Favourite Pet Animals – Tally Marks
Yamini asked her classmates about their favourite pet animals. Each answer was recorded using tally marks.
✔ What are Tally Marks?
Tally marks are a quick way of counting.
- Each line | represents one count
- The fifth line crosses the first four: ||||\
- This group represents $5$
✔ Example
$24 = 5 + 5 + 5 + 5 + 4$
🚗 Vehicles on the Road
Sumita stood on the road and counted vehicles using tally marks.
📋 Making a Table from Tally Marks
After counting, tally marks are converted into numbers and written in a table.
| Vehicle | Number |
|---|---|
| Cycle | 12 |
| Car | 8 |
| Bus | 6 |
🏠 Helping Hands – Using Fractions in Charts
Children shared how they help their parents at home.
Children helping in cooking = $25$
Fraction:
✔ Chapati (Pie) Chart
A chapati chart shows parts of a whole.
- Whole circle = $1$
- Half circle = $\dfrac{1}{2}$
- Quarter circle = $\dfrac{1}{4}$
📺 Ad Mad!! – Counting Advertisements
Ragini counted advertisements during TV breaks.
Ads with children = $10$
Fraction of ads with children:
🌡️ Hot and Cold – Bar Charts
Bar charts are used to compare temperatures of different cities.
Delhi = $33^\circ$C
Shimla = $22^\circ$C
Jaisalmer = $38^\circ$C
✔ Reading a Bar Chart
- Taller bar = higher value
- Shorter bar = lower value
🐇 Rabbits in Australia – Growth Pattern
The number of rabbits increased rapidly every year.
After $1$ year = $18$
After $2$ years = $32$
This shows a pattern close to doubling.
🌱 Growth Chart of a Plant
Amit measured the height of a plant every $4$ days.
Day $8$ → $5.3$ cm
Day $12$ → $9.5$ cm
✔ Understanding Growth Charts
- Horizontal axis → Time (days)
- Vertical axis → Height
🧠 Estimation and Guessing
Charts help us guess values between known points.
✍️ Practice Questions
2) Why are tables useful?
3) Which chart shows parts of a whole?
4) What does a bar chart help us compare?
5) What pattern is seen in rabbit growth?
✅ Quick Revision
✔ Tables organise data
✔ Pie charts show fractions
✔ Bar charts compare values
✔ Growth charts show change with time
🎉 Chapter Complete
After studying this chapter, students can confidently read, make, and interpret different types of charts used in daily life.
📝 Complete Worksheet – Smart Charts
Chapter: Smart Charts
Main Concepts: Tally Marks, Tables, Bar Charts, Pie Charts, Growth Charts 🎯
Section A – Multiple Choice Questions (MCQs)
Q1. Tally marks are mainly used to:
Q2. One group of tally marks (||||\) represents:
Q3. Which chart shows parts of a whole?
Q4. If $\dfrac{1}{4}$ of $100$ students like football, how many students like football?
✔ Q2 → (c) $5$
✔ Q3 → (c) Pie (chapati) chart
✔ Q4 → (b) $25$
Section B – Fill in the Blanks
2) A bar chart is used to __________ values.
3) $\dfrac{50}{100}$ written in simplest form is __________.
4) In a pie chart, the whole circle represents __________.
✔ compare
✔ $\dfrac{1}{2}$
✔ $1$ whole
Section C – Very Short Answer Questions
1) What are tally marks?
2) Name one chart used to compare data.
3) What does a bar chart show?
✔ Bar chart / Pie chart
✔ Comparison of values.
Section D – Short Answer Questions
Q1. Write the fraction for $30$ out of $100$ students.
Q2. Why are tables better than raw data?
Q3. Which bar will be taller: $25^\circ$C or $35^\circ$C? Why?
✔ Tables organise data clearly and neatly.
✔ $35^\circ$C, because it is a bigger value.
Section E – Long Answer Questions
Q1. Explain a pie (chapati) chart with an example.
Q2. A class of $40$ students has the following data: $20$ like cricket, $10$ like football, $10$ like badminton. Write the fraction for each.
✔ Cricket: $\dfrac{20}{40} = \dfrac{1}{2}$
✔ Football: $\dfrac{10}{40} = \dfrac{1}{4}$
✔ Badminton: $\dfrac{10}{40} = \dfrac{1}{4}$
Section F – HOTS / Thinking Questions ⭐
Q1. If the height of a plant doubles every $5$ days, what will be its height after $10$ days if it was $2$ cm initially?
Q2. Which chart is best to show change in height over time? Why?
✔ Growth chart, because it shows change with time.
🎯 Worksheet Complete
✔ Convert numbers into fractions confidently
✔ Observe patterns in data
✔ You are now **exam-ready** ✅