Websites

Lewis and Clark:
http://www.ducksters.com/biography/explorers/lewis_and_clark.php
http://easyscienceforkids.com/all-about-lewis-and-clark/
http://m.american-historama.org/1801-1828-evolution/lewis-and-clark-explorations.htm

Science:
https://a-z-animals.com/animals

Math:

2 Digit Games:
http://www.mathplayground.com/ASB_Canoe_Puppies.html

Place Value Games:
http://www.free-training-tutorial.com/comparing-numbers-games.html
http://www.ictgames.com/sharkNumbers/sharkNumbers_v5.html

All Types of Math Games:
https://www.sumdog.com
http://interactivesites.weebly.com/math.html
https://www.funbrain.com/grade/2
http://classroom.jc-schools.net/basic/math-time.html
http://www.eduplace.com/kids/mw/quiz/g_2.html
https://prodigygame.com/
https://www.frontrowed.com/math/
https://www.eduplace.com/kids/mw/practice/ep_2.html

Reading:
http://www.arbookfind.com/UserType.aspx 
http://interactivesites.weebly.com/language-arts.html