The investigation offered this month is called Ring on a String, and uses Excel to optimise a characteristic of interest (minimise a length in this case).
Click here to see the introductory text for Ring on a String.

Or here if you would like to see one way of solving the problem with a spreadsheet.

Each month there will be an interactive task for a whiteboard or PC screen.

This month's Interactive Task: Make a Copy.

Click here to see guidance notes for Make a Copy
Or here to download the Make a Copy Excel file.

And finally,

This month's tutorial in Excel Techniques :

• Making a Table for a Function of Two Independent Variables.
  
• Inserting an Increment Button.
  
• Using Paste Special to lift a copy of values generated by a formula.