How do I know how many missions I have left for the Grand Prize?

The number of missions for the day is presented on the symbol (In this case a bag of carrots) that presents the mission you are on.
Once you complete a mission, you will see a little V mark on the symbol of the mission you completed. 
When all the symbols have a little V mark on them, it means that you have reached the final mission, and when you complete it you will receive the Grand Prize. 
For example: 
This player has 4 missions to complete and is currently on the 2nd task.