Order of Operations - No Exponents in 5th grade
MathAntics Video (includes exponents which we don't do this year)
Khan Academy - Intro to Order of Operations (Why it's necessary?)
Khan Academy - sample problem, no exponents
Prime and Composite Numbers
Determine if a Number is Prime or Composite Using Area Models
Khan Academy - Recognizing Prime and Composite Numbers
StudyJams - Prime and Composite Numbers
This video from MATHWINGO on Youtube does a great job of showing how to solve expressions using groupings within Order of Operations. In 5th grade we will only use parentheses ( ) and brackets [ ]. This video goes into braces { }, too. You only need to watch up to 9:58 on the video, but you can watch further if you'd like.