Step 2 Objective
Try different approaches and find ways of overcoming difficulties that arise when solving problems.
- 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.
- If you draw another diagram with four lines do you get the same number of crossings?
- Can you explain?
- What different types of diagram can you draw with four lines?
- How did you count the line crossings?
- Tell me why they are different.