Maya walks from home to school. Her graph plots distance from home (km) against time (min), and is described completely here: it starts at (0, 0), rises steadily to (10, 1.2), runs flat to (15, 1.2), then rises more steeply to (20, 2.4). Step 1: Read the axes first - time is the input, distance from home is the output. Step 2: Segment 1, (0, 0) to (10, 1.2): distance grows steadily - Maya walks at a steady speed and covers 1.2 km in 10 min. Step 3: Segment 2, flat from (10, 1.2) to (15, 1.2): time passes but distance does not change - she has stopped for 5 min (say, to talk to a friend). Step 4: Segment 3, (15, 1.2) to (20, 2.4): distance grows faster than in segment 1 (1.2 km in only 5 min) - she hurries the rest of the way and arrives at 2.4 km from home at 20 min. Say it plainly: a story graph is read left to right, one segment at a time, and every change in steepness or direction is something happening in the story.

A graph of a kettle's temperature starts at (0 min, 20°C), rises steadily to (4, 100), then stays flat to (6, 100). What happens in the flat part? -> The water has reached boiling point (100°C) and stays at 100°C while it boils, from minute 4 to minute 6.