This math topic focuses on comparing speeds by requiring conversion between different units of distance (kilometers, meters, centimeters, millimeters) and time (minutes, seconds, hours, days). The problems involve determining which of two given objects (like trains, planes, cars, or bacteria) is traveling faster, after factoring in the conversions necessary to accurately compare their speeds. This advanced section of speed, distance, and time introduces complex problem-solving skills centered around unit conversion and rate comparison.