Step 6 Objective
Identify the necessary information to carry through tasks and solve mathematical problems. Check results and consider whether they are sensible.
- Examples of what pupils should
know and be able to do - Probing questions
- What if pupils find
this a barrier?
What if pupils find this a barrier?
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 all of the diagrams with five (or six) lines:
- How could you organise your results so that they go from smallest to largest number of crossings?
- What patterns can you see?
- Do you think that there are any mistakes? (or explain why you think your results are correct)
- What happens when more than two lines cross at the same point?
How many crossings are there here, one, three or six? Explain.
