krit.club logo

Smart Charts - Pictographs and Bar Charts

Grade 3CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

•

A Pictograph uses pictures or symbols to represent data. A 'Key' is essential to tell us what each picture stands for. For example, if 11 smiley face represents 22 students, then 33 smiley faces represent 3×2=63 \times 2 = 6 students.

A pictograph showing three circles representing six students with a key indicating one circle equals two students.
•

A Bar Chart represents data using rectangular bars of different heights or lengths. The height of each bar corresponds to the value it represents on the vertical axis (Y-axis).

A simple bar chart with three bars of different heights labeled A, B, and C.
•

Tally Marks are a quick way of recording data in groups of 55. We draw four vertical lines and the fifth line crosses through them diagonally.

Illustration of tally marks showing a group of five.
•

Data Interpretation involves reading the charts to find the 'Most Popular' (highest bar/most symbols) or 'Least Popular' (lowest bar/fewest symbols) items.

📐Formulae

Total Value=Number of Symbols×Value of each Symbol\text{Total Value} = \text{Number of Symbols} \times \text{Value of each Symbol}

Difference=Highest Value−Lowest Value\text{Difference} = \text{Highest Value} - \text{Lowest Value}

Total Items=Value of Group A+Value of Group B+…\text{Total Items} = \text{Value of Group A} + \text{Value of Group B} + \dots

💡Examples

Problem 1:

In a pictograph, a symbol of a star represents 44 points. If Rohan has 77 star symbols next to his name, how many points did he score?

Solution:

Step 1: Identify the value of one symbol from the key. 1 star=4 points1 \text{ star} = 4 \text{ points}. Step 2: Count the total number of stars Rohan has, which is 77. Step 3: Multiply the number of symbols by the value per symbol: 7×4=287 \times 4 = 28.

Explanation:

To find the total points, we use the scale provided in the key and multiply it by the count of symbols visible on the chart.

Problem 2:

A bar chart shows that 2525 students like Mango and 1212 students like Apple. How many more students like Mango than Apple?

Solution:

Step 1: Find the value for Mango, which is 2525. Step 2: Find the value for Apple, which is 1212. Step 3: Subtract the smaller number from the larger number to find the difference: 25−12=1325 - 12 = 13.

Explanation:

The phrase 'how many more' tells us to find the difference between two categories. We look at the heights of the two bars and subtract the smaller value from the larger one.

Problem 3:

The following pictograph shows the number of trees planted by different classes. If each tree symbol represents 55 trees, how many trees were planted by Class 3 in total?

A pictograph row showing 4 tree icons for Class 3 with a key stating 1 icon equals 5 trees.

Solution:

From the pictograph, Class 3 has 44 tree symbols. Since 11 symbol =5= 5 trees, Total trees =4×5=20= 4 \times 5 = 20. Class 3 planted 2020 trees.

Explanation:

To find the total, we count the number of symbols for Class 3 and multiply it by the value given in the key (55).

Problem 4:

Look at the bar chart showing the favorite colors of a group of children. How many more children like Blue than Red?

A bar chart comparing Red (value 6) and Blue (value 10).

Solution:

  1. Number of children who like Blue =10= 10
  2. Number of children who like Red =6= 6
  3. Difference =10−6=4= 10 - 6 = 4 44 more children like Blue than Red.

Explanation:

We identify the values of the bars for Blue and Red on the vertical axis and subtract the smaller value from the larger one.