It is important to know how far you're going to be driving on a trip when taking multiple roads to get to your destination. It is similarly important for athletes who run or bicycle long distances to measure how far they've gone. The process of adding miles together requires elementary math and can be done in less than a few minutes.
Write your first measurement down on a sheet of paper or punch it into a calculator if you have one.
Write your second measurement down on the same sheet of paper next to or under the first measurement and include the "+" sign in between both measurements. Press the "+" sign before punching in the second measurement if you're using a calculator.
Add both measurements together mentally and write the end result down. Press the "=" or "Ans" key if you've been using a calculator to find the end result as well. Continue adding any extra measurements to your end result if you have more than two measurements to add.