Here are reading/writing websites:
https://www.funbrain.com/books
For math:
https://www.factmonster.com/math/flashcards
https://www.multiplication.com/games/multiplication-games
https://www.mathsisfun.com/numbers/math-trainer-multiply.html
https://www.mathplayground.com/
https://maths-games.org/fraction-games/
https://vectorkids.com/index.html
https://www.fuelthebrain.com/games/jelly-golf/
This one is for playing card games with your friends:
Here are some more learning sites:
https://online.kidsdiscover.com/
http://kids.nationalgeographic.com/
http://www.sheppardsoftware.com/