I used this slideshow as a starting activity to help get the children thinking how many ways could you share 20 coins (using their knowledge of number bonds) - counters could be used to represent the coins and small hoops could be used for the children to try and find out as many ways as possible the treasure could be shared. (not about sharing equally - make that clear)
Here is a slideshow firstly demonstrating several number bonds or missing number problems (sentences). This activity was based around solving the wizards potion and examples are demonstrated in the slideshow. Very fun activity to start off and recap several number bonds to 10/20!
There are worksheets also available alongside with this activity based on solving the wizards potion, they can be found on my page.