Place four pebbles on the sand in the form of a square. Keep adding as few pebbles as necessary to double the area. How many extra pebbles are added each time?
Article by Bernard Bagnall
Published January 1999,October 2008,February 2011.
How do you know that you have drawn a square?
How will you know that you have found all the possible squares from each point?
You might find it useful to print off this sheet of blank grids if you're not using the interactivity.
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the
NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to
embed rich mathematical tasks into everyday classroom practice. More information on many of our other activities
can be found here.