# Number line activity builder

- Human page: https://happytails.ai/en/education-tools/number-line-activity-builder/
- Markdown: https://happytails.ai/en/education-tools/number-line-activity-builder.md
- Structured JSON: https://happytails.ai/agents/en/education-tools/number-line-activity-builder/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `number-line-activity-builder` |
| Category | education-tools |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Use the visible action or interactive controls. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | Not callable through HTTP. |
| Browser-agent interface | run_current_tool |

### Implementation notes

Enter points and jumps using fractions, mixed numbers or decimals. Hidden point labels use letters and jump sizes are removed; tick values stay visible. Print both SVGs at 100% to preserve the chosen line length.

### Inputs and settings

Text input: Your text.

Example or placeholder shown in the interface (not a validated fixture):

```text
Type or paste your input…
```

Up to 20,000 characters. Review the settings before running.

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `start` | Start | text | "0" |  |
| `end` | End | text | "2" |  |
| `step` | Tick step | text | "1/4" |  |
| `lengthMm` | Line length (mm) | number | 180 | min=60 max=260 step=1 |
| `tickFormat` | Tick labels | select | "Mixed numbers" | Allowed: Fractions, Mixed numbers, Decimals |
| `labelEvery` | Label every Nth tick (0 for automatic) | number | 0 | min=0 max=100 step=1 |
| `hideAnswers` | Hide point values (letters on the worksheet) | checkbox | true |  |

### Browser-agent workflow

1. Open the human page in a browser that supports WebMCP.
2. Discover the interface exposed by that page; use its actual schema.
3. Select files on the page first when the tool requires files.
4. Call `run_current_tool` with valid input and settings.
5. Inspect the returned result or error and the displayed output. Retrieve files from the displayed download links.

Calls do not automatically copy or download results. Browser permissions still apply. Interface availability alone is not proof of successful execution.

### Planning specification

Start and end are bounded to ±1,000,000, with 2 to 201 ticks, a 60 to 260 mm line, up to 26 points, 20 jumps and 20,000 item characters. Hidden point values use letters and jump-size labels are omitted; tick values remain visible. Print at 100% to preserve the chosen line length. The tool cannot verify printer scaling.

This describes intended requirements. Use the implementation notes, interface schema and observed output to determine current support.

### Complete machine-readable capability record

```json
{
  "id": "number-line-activity-builder",
  "category": "education-tools",
  "built": true,
  "requirements": "Start and end are bounded to ±1,000,000, with 2 to 201 ticks, a 60 to 260 mm line, up to 26 points, 20 jumps and 20,000 item characters. Hidden point values use letters and jump-size labels are omitted; tick values remain visible. Print at 100% to preserve the chosen line length. The tool cannot verify printer scaling.",
  "implementation": {
    "fields": [
      {
        "key": "start",
        "label": "Start",
        "value": "0",
        "type": "text"
      },
      {
        "key": "end",
        "label": "End",
        "value": "2",
        "type": "text"
      },
      {
        "key": "step",
        "label": "Tick step",
        "value": "1/4",
        "type": "text"
      },
      {
        "key": "lengthMm",
        "label": "Line length (mm)",
        "value": 180,
        "type": "number",
        "min": 60,
        "max": 260,
        "step": 1
      },
      {
        "key": "tickFormat",
        "label": "Tick labels",
        "value": "Mixed numbers",
        "type": "select",
        "values": [
          "Fractions",
          "Mixed numbers",
          "Decimals"
        ],
        "labels": {
          "Fractions": "Labels as fractions"
        }
      },
      {
        "key": "labelEvery",
        "label": "Label every Nth tick (0 for automatic)",
        "value": 0,
        "type": "number",
        "min": 0,
        "max": 100,
        "step": 1
      },
      {
        "key": "hideAnswers",
        "label": "Hide point values (letters on the worksheet)",
        "value": true,
        "type": "checkbox"
      }
    ],
    "registrationFamily": "learning-activities-reference",
    "presentation": "metrics",
    "inputMaxLength": 20000,
    "inputErrorCode": "LEARNING_ACTIVITIES_REFERENCE_TOO_LONG",
    "note": "Enter points and jumps using fractions, mixed numbers or decimals. Hidden point labels use letters and jump sizes are removed; tick values stay visible. Print both SVGs at 100% to preserve the chosen line length.",
    "experience": {
      "automatic": false,
      "single": false,
      "inputMaxLength": 20000,
      "inputMode": "text",
      "label": "Your text",
      "placeholder": "Type or paste your input…",
      "help": "Up to 20,000 characters. Review the settings before running.",
      "helpParts": [
        "Up to 20,000 characters.",
        "Review the settings before running."
      ],
      "action": null
    },
    "mode": "explicit",
    "interactive": false
  },
  "execution": "Browser interface",
  "api": null,
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}
```

## Page guide

Place points and jumps on an exact number line, with an optional worksheet and answer key.

### How to use Number line activity builder

1. Set the start, end and tick step using whole numbers, decimals or fractions.
2. Enter point,value or jump,from,to, one per line.
3. Choose tick labels, line length and whether point labels are hidden.
4. Generate, then download the worksheet SVG, answer-key SVG and CSV.

How can we improve this tool?

Report a problem or share an idea.

Please leave out private information. Your message and the tool name go to our team via PostHog.

## Useful next steps

- [Coordinate Plotting Worksheet](https://happytails.ai/en/education-tools/coordinate-plotting-worksheet/) ([Markdown](https://happytails.ai/en/education-tools/coordinate-plotting-worksheet.md))

- [Graphing calculator](https://happytails.ai/en/calculators/graphing-calculator/) ([Markdown](https://happytails.ai/en/calculators/graphing-calculator.md))

Start and end are bounded to ±1,000,000, with 2 to 201 ticks, a 60 to 260 mm line, up to 26 points, 20 jumps and 20,000 item characters. Hidden point values use letters and jump-size labels are omitted; tick values remain visible. Print at 100% to preserve the chosen line length. The tool cannot verify printer scaling.

## Use exact values

Points and jumps use integer, fraction, mixed-number or decimal values that fit the selected range and tick interval.

### Hidden point answers

The worksheet replaces point values with letters and removes jump-size labels. Tick values stay visible; the separate answer key contains values.

### Preserve the selected length

Print the SVG at 100% actual size. The exported SVG may be wider than a common page to keep long endpoint labels inside the drawing without shrinking the axis.