Lesson Notes By Weeks and Term v5 - Grade 4

Lesson Video

This page supports the lesson note with a companion video and a short classroom-ready summary.

For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.

Performance objectives

• Collect data using tally marks.
• Show data in a pictograph with a key.
• Create a bar graph with labels and a scale.
• Answer questions using your graphs.
• Compare different ways of showing data.

Lesson summary

Data handling is a crucial skill in mathematics and in everyday life. It involves collecting, organizing, representing, and interpreting information. In South Africa, data handling helps us understand trends in our communities, from the popularity of different sports to the number of learners in schools. It empowers us to make informed decisions based on evidence, rather than just guessing. This week, we will focus on collecting data using tally marks and representing it in pictographs and bar graphs. We will learn how to read and interpret these graphs to answer questions about the data.

Lesson notes

a)

Data Collection with Tally Marks: Tally marks are a simple and efficient way to collect data. Each vertical line represents one item or occurrence. A group of five is represented by four vertical lines and a diagonal line crossing them (like a gate). This makes it easy to count groups of five.

Example: Let's say we are surveying learners in our class about their favourite fruits. | Fruit | Tally Marks | Number | | -------- | ----------- | ------ | | Apple | IIII | 4 | | Banana | II II | 7 | | Orange | III | 3 | | Mango | IIII I | 6 | | Grapes | II | 2 | b)

Pictographs: A pictograph uses pictures or symbols to represent data. Each picture represents a certain number of items. It's crucial to have a key that tells you how many items each picture represents.

Example: Using the fruit data from above, let’s create a pictograph. Let's say one smiley face represents 2 fruits. | Fruit | Pictograph | | -------- | ------------------------------------------------------------------------------------------------------------ | | Apple | 🍎🍎 | | Banana | 🍌🍌🍌 🍌 | | Orange | 🍊🍊 🍊 | | Mango | 🥭🥭🥭 | | Grapes | 🍇🍇 | Key: 🍎 = 2 Apples; 🍌 = 2 Bananas; 🍊 = 2 Oranges; 🥭 = 2 Mangos; 🍇 = 2 Grapes

Note: Half a symbol would represent half the amount specified in the key. For example, if there were only 1 apple, we'd use half an apple symbol. c)

Bar Graphs: A bar graph uses bars of different lengths to represent data. The length of each bar corresponds to the quantity it represents.

Bar graphs have two axes: a horizontal axis (usually showing categories) and a vertical axis (showing the scale). It’s important to choose an appropriate scale so the graph is easy to read. Make sure you include labels!

Example: Using the fruit data again: Horizontal Axis: Fruits (Apple, Banana, Orange, Mango, Grapes)

Vertical Axis: Number of Learners (Scale: 0, 1, 2, 3, 4, 5, 6, 7) The bars would be drawn to the height corresponding to the "Number" column in the tally chart. ``` 7 | * 6 | 5 | 4 | * 3 | 2 | * 1 | * 0 |---------------*--- Apple Banana Orange Mango Grapes ``` d)

Comparing Representations: Different representations highlight different aspects of the data. Pictographs are visually appealing, while bar graphs are more precise for comparing quantities. The key is to choose the representation that best communicates the information. Guided Practice (With Solutions)

Question 1: The Grade 4 class conducted a survey about their favourite South African animals.

Here are the results: Lion (8), Elephant (6), Giraffe (4), Zebra (5), Springbok (7). Use tally marks to record this data.

Solution: | Animal | Tally Marks | Number | | ----------- | ----------- | ------ | | Lion | IIII IIII | 8 | | Elephant | IIII I | 6 | | Giraffe | IIII | 4 | | Zebra | IIII I | 5 | | Springbok | IIII II | 7 |

Commentary: Tally marks are easy to create as we go. Make sure to group them into fives for easy counting.

Question 2: Represent the data from Question 1 in a pictograph. Let one animal picture represent 2 animals. Use the animal emoji.

Solution: | Animal | Pictograph | | ----------- | ------------------------------------------------------------ | | Lion | 🦁🦁🦁🦁 | | Elephant | 🐘🐘🐘 | | Giraffe | 🦒🦒 | | Zebra | 🦓🦓 🦓 | | Springbok | 🦌🦌🦌 🦌 | Key: 🦁 = 2 Lions; 🐘 = 2 Elephants; 🦒 = 2 Giraffes; 🦓 = 2 Zebras; 🦌 = 2 Springboks

Commentary: Notice how we had to use half an emoji for the Zebra and Springbok since the data was odd.

Question 3: Represent the data from Question 1 in a bar graph. Choose an appropriate scale for the vertical axis.

Solution: ``` 8 | * 7 | 6 | * 5 | 4 | * 3 | * 2 | * 1 | * 0 |---------------*--- Lion Elephant Giraffe Zebra Springbok ```

Commentary: We chose a scale from 0 to 8, increasing by

1. This is appropriate as the data ranges from 4 to

8. Independent Practice (Questions Only) A tuck shop sold the following number of snacks in a week: Chips (12), Sweets (15), Chocolates (9), Biscuits (10), Fruit (6). Use tally marks to record this data. Represent the data from Question 1 in a pictograph. Let one snack icon represent 3 snacks. Represent the data from Question 1 in a bar graph. Choose an appropriate scale. Which snack was the most popular? (Use your graph from Question 3). How many more sweets were sold than chocolates? (Use your tally marks from Question 1, or the graphs you've created.) If each snack costs R5, calculate the total revenue for each snack type (Chips, Sweets, Chocolates, Biscuits, Fruit). You can present this information in a new tally chart. The following data was obtained by asking learners what type of transport they use to get to school. Bus(15), Walk(20), Car(10), Taxi(25). Represent this data in a bar graph. Which form of transport is the most popular? Which form of transport is the least popular? How many more learners take a taxi to school as opposed to those who go by car? What is the total number of learners who participated in the survey?