1. Distance: How far something travels.

2. Time: How long it takes to travel that distance.

Formula:

Speed = Distance / Time

Units:

* Distance: Usually measured in meters (m), kilometers (km), miles (mi), or feet (ft).

* Time: Usually measured in seconds (s), minutes (min), or hours (hr).

* Speed: Usually measured in meters per second (m/s), kilometers per hour (km/h), miles per hour (mph), or feet per second (ft/s).

Example:

Let's say a car travels 100 kilometers in 2 hours. To calculate the car's speed:

Speed = Distance / Time

Speed = 100 km / 2 hr

Speed = 50 km/h

Therefore, the car's speed is 50 kilometers per hour.

Tips:

* Make sure the units of distance and time are consistent.

* If you are given the speed and one other variable (distance or time), you can rearrange the formula to find the missing variable.

* For example, if you know the speed and distance, you can find the time by rearranging the formula to: Time = Distance / Speed.