You may want to let them try and work out how long it will take you to travel somewhere when you get in the car, by telling them what speed you'll be traveling and how far away your destination is.
This affords me the opportunity to publicize World Maths Day which took place on the first Wednesday in March. There students of all ages from all over the world went online (it's free) to play mental math against each other. Last year 287ꯠ students from 98 countries participated to answer over 38 million questions. This year they hoped to break 50 million questions and did so magnificently answering over 150 million questions and I am sure they had great fun doing it.