Mr Smith and Mr Jones are two maths teachers. By asking questions, the answers to which may be right or wrong, Mr Jones is able to find the number of the house Mr Smith lives in... Or not!
An introduction to the binomial coefficient, and exploration of some of the formulae it satisfies.
Select any 15 cards from a pack and lay them out on the table - face up - in three equal columns.
Why does this trick always work?
Are there any other numbers of cards for which this works?