There was a time that the United States of America had some of the highest mathematic scores in the world for students in grades k through 12. A lot has changes since those days, and in order to help children get back on the path to being good mathematical students parents need to play an important role.
While the newer method does require computer access for every child, most schools now have that capability. As children do more hands-on learning on computers and less in books, these programs are capable of reaching them on a level they can understand.
Get in the Kitchen! I was very hesitant for a while with my son when it came to the kitchen. I worried about the GIANT mess that would be left when he was done "helping". You don't even have to take on the entire project with them! You can start small and let your child help with measuring certain ingredients. You can modify the difficulty of the 'lesson' by talking about the different kinds of measuring cups and seeing what other measurements can also add up to equal one cup, etc.
Go on a counting scavenger hunt! For young children, you can keep the hunt simple and indoors, go on a hunt and count how many bedrooms, windows, doors, bathrooms, etc are in your house. For older children, you can even take this adventure outside. Look for certain kinds of animals, plants, flowers, you name it! Add in another element of fun (for any age) and create a graph for them to track their finds!