The following websites are linked with concepts in the Ontario Junior Math Curriculum. If you know of any other websites that would be good additions to the list please leave a comment at the bottom of the page.
All Math Strands
National Library of Virtual Manipulatives: http://nlvm.usu.edu
mathFROG: http://cemc2.math.uwaterloo.ca/mathfrog/
Number Sense and Numeration
Change Maker: http://www.funbrain.com/cashreg/
ToonUniversity: http://www.toonuniversity.com/g_cat_m.asp
Clara Fraction’s Ice Cream Shop: http://www.mrnussbaum.com/clarafraction.htm
Patterning and Algebra
Measurement
Area and Perimeter: http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/maths/perimeter_and_area/index.html
Data Management and Probability
Geometry