This tool is a small part of TEST4U, used mainly for demonstration purposes. It contains 5 questions – 2 for Core level and 3 for Expert.
First, click on the following link to open the tool.
Then, select the level by clicking one of the available buttons.
For each question, there are detailed instructions, explaining what you have to do in order to solve the question.
Note that a Spreadsheet editing application is required. You can use MS Office Excel, OpenOffice/LibreOffice Calc, Google Spreadsheets or even an Android/iOS mobile application.