http://www.mathgames.com/grade4
 

Set up by teachers

 
http://catalog.mathlearningcenter.org/apps
 


Number & Operations in Base Ten

 http://education.jlab.org/placevalue/


Number & Operations—Fractions


Measurement & Data

https://www.brainpop.com/games/areabuilder/

Geometry

 http://smart-games.org/en/set/find_set
http://wodb.ca/index.html