Become a Math Whiz!
http://www.hbschool.com/glossary/math_advantage/glossary2.html
http://www.woodlands-junior.kent.sch.uk/maths/interactive/numbers.htm#Place - Practice Place Value Skills
http://www.eduplace.com/kids/hmm/g_2.html
http://www.woodlands-junior.kent.sch.uk/maths/numberskills.html