Taken from YouTube (www.youtube.com/watch?v=rQAjo9J_yL8)
A clear explanation of how to divide by chunking. His layout is slightly different to the way I do it, but he is very clear and the method is the same.
This is a two player game.
Each player takes it in turn to place a counter over one of the numbers.
When a counter is placed on the board the number is added to the total of previous numbers.
This total is kept between the two players – not one total each. It is a good idea to record this on paper!
Each player tries to make the total come to exactly 31. The player who does so is the winner.
If a player places a counter to make the total over 31 he/she loses.