Math worksheet for drawing bar charts from tally charts, featuring bird data and a blank graph for students to fill in.

Problem Overview:

The task involves creating a bar chart based on the data provided in a tally chart. The tally chart shows the number of sightings for different bird species in a garden. The goal is to convert this tally data into numerical values and then represent it visually using a bar chart.

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Step-by-Step Solution:

#### 1. Understand the Tally Chart:
A tally mark represents one count. A group of five tally marks (four vertical lines and one diagonal line crossing them) represents 5 counts. We need to count the tally marks for each bird species and convert them into numerical values.

#### 2. Count the Tally Marks:
Let's count the tally marks for each bird species:

- Robin:
- Tally: |||| |||| ||||
- Total: \( 5 + 5 + 5 = 15 \)

- Blue tit:
- Tally: |||| |||| |||| |||
- Total: \( 5 + 5 + 5 + 3 = 18 \)

- Wren:
- Tally: |||| ||
- Total: \( 5 + 2 = 7 \)

- Goldfinch:
- Tally: |||| |||
- Total: \( 5 + 3 = 8 \)

- Blackbird:
- Tally: |||| |||| |||
- Total: \( 5 + 5 + 3 = 13 \)

- Nuthatch:
- Tally: |||| |||| |
- Total: \( 5 + 5 + 1 = 11 \)

#### 3. Organize the Data:
Now, we have the numerical data for each bird species:

| Bird | Number of Sightings |
|------------|----------------------|
| Robin | 15 |
| Blue tit | 18 |
| Wren | 7 |
| Goldfinch | 8 |
| Blackbird | 13 |
| Nuthatch | 11 |

#### 4. Draw the Bar Chart:
We are given a blank bar chart with the x-axis labeled with the bird species and the y-axis representing the number of sightings. The y-axis ranges from 0 to 26.

- Robin: Draw a bar reaching up to 15.
- Blue tit: Draw a bar reaching up to 18.
- Wren: Draw a bar reaching up to 7.
- Goldfinch: Draw a bar reaching up to 8.
- Blackbird: Draw a bar reaching up to 13.
- Nuthatch: Draw a bar reaching up to 11.

#### 5. Label the Chart:
- Title the chart: "Number of Bird Sightings in the Garden."
- Label the x-axis: "Bird Species."
- Label the y-axis: "Number of Sightings."

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Final Answer:

The bar chart should be drawn as follows:

- Robin: Bar height = 15
- Blue tit: Bar height = 18
- Wren: Bar height = 7
- Goldfinch: Bar height = 8
- Blackbird: Bar height = 13
- Nuthatch: Bar height = 11

The final answer is represented by the completed bar chart. If you need a visual representation, you can draw it manually or use graphing software to create it.

Final Answer:
\[
\boxed{\text{Bar chart with heights: Robin (15), Blue tit (18), Wren (7), Goldfinch (8), Blackbird (13), Nuthatch (11)}}
\]