Step 6 Objective

Show understanding of situations by describing them mathematically, making correct use of symbols, words, diagrams, tables and graphs.


What if pupils find this a barrier?

diagram showing three lines crossing

Line Crossings

  • Draw three straight lines (line segments) so that some cross over each other.
  • How many crossings are there?
  • Try different arrangements of the lines. What is the maximum number of possible crossings?
  • Try using more lines.
  • Is there a rule for the maximum for any number of lines? If so, write it down.

Use the problem Line Crossings.

You have drawn a lot of diagrams.

  • Can you show the results for different numbers of lines together?
  • What information would you put into a table of results? Can you draw this table?