Step 8 Objective

Interpret, discuss and synthesise information presented in a variety of mathematical forms. Begin to explain reasons for selection and use of diagrams.


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.

Look at your table of results:

  • Explain to me what it shows and what it means. How would you write this down?
  • How would these results help you to explain what happens when you add another line?