Car Games 

Odd
or Even What are the chances? 
Game for two players  Have each child
guess if there are more license plates that end in an odd or even
number. (plates that end in a letter do not count) 1. Give each child a blank sheet of paper and a pencil, or something to mark with. 2. Set a time limit, usually 1015 minutes. 3. Have one child look for plates that end in an odd number, and the other look for an even number. 4. A tick mark or dash should be marked for each car they find. (For extra learning, have them group the marks in sets of 5) 4. At the end of the time limit, have the children add up their marks. (Counting by 5's if grouping was used) 
I Spy  Pick out an object that everyone can see. Then give them a clue by saying, "I spy something ..." (Say its shape, color or size) The other players ask questions about what you see and you only answer with "yes" or "no". The first player who guesses right becomes the new spy. 
A to Z  Find words beginning with "A", on signs around you. Have the players take turns, after "A", go to "B", and so on. Can you get ot "Z" and finish the alphabet? Alternate the starting person at the start of a new game, so that everyone gets a chance with the challenging letters. (For younger players you may want to skip the difficult letters.) 
What did I bring on my trip?  Start this game out by saying, "I'm going on a trip and I'm bringing..." . The first player should name an item that starts with the letter "A". After "A" , the next player will say the same thing but with the letter "B", and so on. 
Guess the number  Let your child think of a number between
a stated range of numbers. You try to guess the number by asking
questions. Here's a sample of how it might go: Your child: I'm
thinking of a number between 1 and 100. You ask: Is it more
than 50? Your child: No. You: Is it an even number?
Child: No. You: Can you divide this number into three equal
parts? And so forth. After you have guessed the number, let your
child guess a number that you are thinking of by asking similar
questions.
One benefit of this game is that, by asking questions about numbers, it helps the child to develop an understanding of some concepts, characteristics and meanings of numbers. If your child doesn't know the difference between odd and even numbers, this is an opportunity to explain and help them understand. 
License Plate  You call out the number on a license plate and see who can add up the numbers correctly. Ask, How did you do that? Another license plate game is to copy down the number on the plate. Ignore any letters and read the number out loud, for example: M663218 would be six hundred sixtythree thousand, two hundred eighteen. 
Are We There Yet?  Try grappling with the Are we there
yet? questions with a little diversionary questioning of your own.
Ask your child questions about how far you're traveling. Yards? Miles?
Kilometers maybe? How fast are we going? If it's 3:15 now, and it
takes us two hours to get there, what time will we arrive? How far
have we gone?
Some of the other activities you might try while in transit is to have the kids watch for numbers on streets and buildings, phone numbers on the sides of trucks and other vehicles, dates on buildings, or business signs with numbers in them. 