2. Draw a coordinate system on the upper right, and mark the amount of tea to be brewed on the coordinate axis, that is, the abscissa is marked X and the ordinate is marked Y..

3. The teapot capacity is represented by a line segment, that is, draw a line segment on the X axis of the abscissa, from the point (0, teapot capacity) to the point (teapot capacity, teapot capacity) on the Y axis.

4. Draw a line segment on the X axis of the abscissa, from the point (0, the amount of tea brewed) to the point (the amount of tea brewed, the amount of tea brewed) on the Y axis.

When two line segments intersect, you can get the answer. The answer is the amount of water added, that is, the capacity of the teapot MINUS the amount of tea to be brewed.