CoolMath4Kids has online lessons, interactive practice sets, puzzles and games for fourth graders. Its lessons go up to the fifth-grade level and include addition, subtraction, multiplication, division, fractions and decimals. The Brain Bender section has dozens of virtual math games and the Lessons section offers graphic instructions with interactive multiplication, division and fraction questions. The site also has multiplication and division flash cards that can be printed out and colored in with crayons or pens.
Quizlet has over 150 sets of fourth grade math flash cards that you can either print or use as virtual flash cards online. Each of these flash card sets comes with interactive lessons about the flash card topics, which include graded answers to the questions. There also is an online test that accompanies each flash card set. These tests can be set to a specific grade for letter capitalization, punctuation and use of parenthesis, in addition to the test content. Each flash card set also comes with an online list of math terms and definitions with audio that says each word and definition if desired. Quizlet also has two virtual math games that are appropriate for fourth graders: Scatter and Space Race.
The National Library of Virtual Manipulatives has approximately 100 interactive math games for grades three through five on its website. Games range from tangrams, which give players geometrical shapes and then challenge them to create objects with the shapes, to dominoes using different shapes in a game of polyominoes or pentominoes. Play with online spinners to study probability and generate geometric fractal art. Topics include number operations, algebra, geometry, measurements, data analysis and probability.
FunBrain lists math games on its website by age or grade level. You can adjust the age to your choice or use age 9 as the approximate age of fourth graders. You can also see a list of math games by grade level on this site. On FunBrain's home page, you can choose between the math arcade, which is full of games, or Classic FunBrain games such as math baseball and math car racing. Sudoku puzzles are available for online play or you can print the puzzles.