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.
A parent must know what level of math and any other subject, for that matter, that their child is performing at every school year. When children enter kindergarten and the school recommends that children know their ABC's and know how to count to twenty or whatever number, it is the parent's responsibility to make sure the child is prepared prior to enrolling in school.
Elementary math is the building block on more complex topics that students must learn for the future. From simple addition and subtraction to telling time, it is a fundamental knowledge base used throughout life. Computers are also a basic fundamental building block for the future. Math programs integrate both.
Some of the software is developed in a game format. Children will think that they are playing a game, but in reality are actually learning math. Technology can be great, but I must warn parents to not allow children to spend a lot of unsupervised time on the computer.