Poetry4Kids - The largest collection of poetry for kids on the internet. In addition to poems, this site has activities, games, podcasts, and a rhyming dictionary.
Read, Write, Think - Sort a wide range of games, tools, activities, and projects by grade level or skill for a large collection of reading resources.
Scholastic - This site offers many activities to enhance student's reading abilities sorted by grade levels.
Illuminations - Check out the Interactivities tab for many math activities to explore various math concept for all ages.
Khan Academy - You can learn anything. Expert-created content and resources for every subject and level. Free online Math Lessons sorted by subject or grade.
Order of Operation - This is a set of drills to teach order of operation with addition, subtraction, multiplication, and division.
Scholastic - This site has many math games sorted by grade level.