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.
For those parents who are too busy with work, an online math course is one way to show your kids how to have fun with math. You can find lots of math worksheets on the site where you can formulate addition, subtraction, multiplication, and division worksheets. You can also find on the site ways or methods on how to teach your kids that math is fun and not boring. Have fun with math!!!