Figure 4.4: The Answer Editor for the Numberline

The Answer Editor for the numberline consists of a numberline and tools for placing full and empty endpoints and segments (Fig. 4.4). To place a segment, mark a point on the numberline with the pencil, then click on that point with either the full or the empty tool. To place a segment, use the Region tool to click on any point in the relevant part of the numberline. If the user clicks between two endpoints, the segment will extend to each of them. When the user clicks between an endpoint and an extremity of the numberline, the segment will appear with an arrow to indicate that it continues to infinity. Click with the eraser to remove any part of the construction.