There are several ways to determine the distance and amount of time a trip will take. For example, if the traveler knows that his or her car travels 20 miles for every gallon of gas in the tank, he or she could represent the total number of miles it is possible to drive based on how much gas is put into the tank. This can be expressed as 20g, in which g stands for the number of gallons in the tank. For example, if someone bought 10 gallons of gas to reach a destination (10 gallons × 20 miles/gallon), the traveler can go about 200 miles (the gallons in the top and bottom of the equation cancel each other out, leaving miles).

Another example involves cars and mileage. If the traveler drives down a highway at a steady rate of 65 miles per hour, the driver can determine how long it will take to get to a destination, especially if he or she knows how many miles it is to that destination. The equation is mileage divided by 65 miles per hour (m/65). For example, if the traveler is going 650 miles, the (650 miles)/(65 miles per hour) equals 10 hours (the miles in the top and bottom of the equation cancel each other out, leaving hours).