Here are some helpful links (as requested by many families at conferences):
Learn Alberta Grade 4 Curriculum At a Glance: www.learnalberta.ca/content/mychildslearning/gradeataglance/grade4.pdf
Math - Learn Alberta Grade 4 "Raft Race" - www.learnalberta.ca/content/me4rr/
Math - Check out Number Sense and Patterns sections in October - ca.ixl.com/math/grade-4
Math - Try chapters 1,2 in Nelson Education sample: www.nelson.com/school/elementary/mathK8/math4/studentcentre/studtryout.html#ch1
Math - Problem Solving: www.aplusclick.com/grade4.htm
Math - games: www.mathplayground.com/grade_4_games.html
Math - Khan Academy (although they are US based, they have tutorials to help) Place Value would be a good review: www.khanacademy.org/math/cc-fourth-grade-math#table-of-contents
Math- games: www.mathgames.com/
Math - lessons - www.e-learningforkids.org/math/grade/4/
Math - Virtual Manipulatives (to help practice concepts): www.glencoe.com/sites/common_assets/mathematics/ebook_assets/vmf/VMF-Interface.html
Math - More digital manipulatives (geoboard): catalog.mathlearningcenter.org/apps
Math - 'Math Mavens Mysteries' solve problems (audio support): teacher.scholastic.com/maven/index.htm
Math - Study Jams (has 'test yourself', teacher notes and various topics): studyjams.scholastic.com/studyjams/jams/math/index.htm
Math - Math Master - worksheets, videos: mathmaster.org/
Math - word problems: www.internet4classrooms.com/skill_builders/word_problems_math_fourth_4th_grade.htm
Critical Thinking - tips for parents: tip.duke.edu/node/822
Reading Comprehension - www.k5learning.com/reading-comprehension-worksheets/fourth-grade-4
National Geographic - Sample - to read: nationalgeographic.org/education/explorer-magazine/sample-issues
Kids News - www.dogonews.com/
Story Online (listen to books read by celebrities): www.storylineonline.net/
Spelling - old fashioned Spelling Bee: www.learner.org/interactives/spelling/index.html
Spelling City - www.spellingcity.com/
Spelling Games or Challenges (BBC) - www.bbc.co.uk/schools/spellits/ad_menu_flash.shtml