Answer: The difference between the allocated hours and the hours spent on the project
Explanation:
In Odoo 18, when you view tasks or projects (especially in the Kanban or list views), you may see a red number on the right-hand side. This number shows how much the task or project is deviating from its planned time budget. It is calculated as:

Allocated Hours – Hours Spent (from timesheets)

• If the result is positive, it means there is still time remaining within the allocated hours.
  
  

• If the result is negative, it means more time has been spent than was planned — this is why the number appears in red, to highlight a time overrun.
  
  

This helps project managers and team members track time efficiency and quickly identify tasks or projects that are exceeding their estimated effort.