This exploratory problem is a fantastic way to consolidate
  children's understanding of halving and halves. Pupils will have
  many ideas of their own when it comes to checking or proving that
  the squares really are split in half. Some will count squares if
  drawn on squared paper. Others may want to cut out the squares
  and physically lay the halves on top of each other.
  Alternatively, it might be possible in some instances to cut out
  the square and fold it to show that it has been split in half.
  You might like to distinguish between the squares that have been
  divided into two pieces (one red, one white) from those where
  there are more than two pieces. You could use the PowerPoint
  presentation which is linked to from this site:
  http://www.icteachers.co.uk/resources/resources_numeracy.htm in
  the Number section under "fractions". It shows squares being
  divided in different ways (although not always in half) and would
  provoke a nice introductory discussion to this problem. <br />