Simultaneous equations

In this interactivity each fruit has a hidden value. Can you deduce what each one is worth?

There are lots of different methods to find out what the shapes are worth - how many can you find?

Can you find the values at the vertices when you know the values on the edges?

How have "Warmsnug" arrived at the prices shown on their windows? Which window has been given an incorrect price?

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?

All CD Heaven stores were given the same number of a popular CD to sell for £24. In their two week sale each store reduces the price of the CD by 25% ... How many CDs did the store sell at each price?

There is a particular value of x, and a value of y to go with it, which make all these five expressions equal in value. Can you find that x, y pair?

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 bigger, n+10 or 2n+3? Can you find a good method of answering similar questions?

Can you find the values at the vertices when you know the values on the edges of these multiplication arithmagons?