Read the Graph of a Function

Each question gives you the graph of a function f and eleven things to work out from it. Nothing has to be calculated - every answer is read off the picture. The dots mark the points that sit exactly on a corner of the grid, and the graph stops at the dot on each end.

Here is how to read it:

To find $f(3)$, go to 3 on the x-axis, up or down until you hit the curve, then straight across to the y-axis. That is the height of the curve above 3.
The x-intercepts are where the curve crosses the x-axis, so they are the values of x with $f(x) = 0$. The y-intercept is the single height $f(0)$.
$f(x) > 0$ where the curve is above the axis and $f(x) < 0$ where it is below. The curve changes side only at an x-intercept.
The domain is how far the graph reaches from left to right, the range how far it reaches from bottom to top - so the range runs from the lowest point of the curve to the highest.
To count how often the line $y = c$ meets the graph, draw that level line across the picture and count the crossings. An upright line $x = a$ can meet it at most once, because a function has only one value for each x - that is the vertical line test.
Increasing means the curve rises as you read from left to right, decreasing means it falls.

Reload the page and you get a new worksheet - both graphs are generated at random every time.