For Multiplication:
http://www.free-training-tutorial.com/times-tables-games.html
http://www.internet4classrooms.com/skill_builders/multiplication_math_fourth_4th_grade.htm
For Science Vocabulary:
http://quizlet.com/5016585/4th-grade-science-vocabulary-flash-cards/
http://quizlet.com/206981/deauville-gardens-4th-grade-science-vocabulary-flash-cards/