### Intersections

Change one equation in this pair of simultaneous equations very slightly and there is a big change in the solution. Why?

### Negatively Triangular

How many intersections do you expect from four straight lines ? Which three lines enclose a triangle with negative co-ordinates for every point ?

### Which Is Cheaper?

When I park my car in Mathstown, there are two car parks to choose from. Can you help me to decide which one to use?

# Which Is Bigger?

##### Age 14 to 16 Challenge Level:
Can you fill in the rest of the table below?

 $n$ $n+10$ $2n+3$ 4 14 11 5 6 7 8 9 10 20 23

What do you notice?

How else could you represent this information?