Step 4 Objective
Make general statements, based on evidence produced, and explain reasoning.
- 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 the different diagrams with six (five) lines.
- When there are only a few crossings what can you say about the lines?
- What do the lines look like when there are a lot of crossings?
- Explain how you can get more (or fewer) crossings?
With five lines I can draw a lot of patterns with different number of crossings.
When lines are parallel there are no crossings.
You have to be careful because if you make some lines longer they will cross other lines.
The more jumbled the picture the more crossings there are.
