Parents can assist with developing a lot of the fundamental skills needed for children to succeed in math when they attend school. Parents can do things that will support the schools and hopefully the schools will do the rest.
The same general idea worked when it came to my son's Lego's! It was a great way to work on patterns and following directions! I would draw a pattern on paper for him to copy and recreate with his Legos. It not only helped with his color recognition, but his problem solving skills, fine motor skills and he didn't even know he was doing math!!
They can start with asking simple math questions and going on to harder questions, as the child gets older. Parents should continually ask children mathematical computation questions and give positive feedback when they respond. Children love to receive positive feedback and that encourages continues growth.
Anything less could cause children to suffer a tremendous loss. The teacher that parents should be trusting to teach their child math is a person that will challenge their child regardless of their age. In addition to the challenges, the teacher should encourage children to try hard. Children need to know that their teacher cares about them and is not just trying to give them a lot of hard work.