Here are suggested links that have the opportunity to help your child learn to add and subtract.
The first one can be found on the Computation Practice page of the math web site. It is called AAA Math and deals with arithmetic lessons.This is a link to the addition topics, but you can get many arithmetic topics (including subtraction) by using the links in the yellow sidebar.
http://www.aaastudy.com/add.htm
http://www.mathplayground.com/thinkingblocks.html
These sites can be changed to practice subtraction, multiplication and division.
XtraMath
http://www.mathsisfun.com/numbers/math-trainer-addition.html
http://www.thinkingblocks.com/ThinkingBlocks_AS/TB_AS_Main.html
Prodigy
Other FUN sites!
Fact Fluency
Terrific Triangles
Teaching Time
Graphing
Funbrain
Multiplication Games
Multiplication Chart Lessons
Factors
Fractions
Percentages
Research:
Epic!
Typing:
Typing Agent
Typing.com
Turtle Diaries
Kidz Type
Vocabulary:
Free Rice
Graphing
Graphing