Everyone talks about using math strategies but nobody ever defines what they look like! Here's the definition of each math strategy. These are essential for kids to get really comfortable composing and decomposing numbers as required in CCSS.
These posters are appropriate for all grade levels but I would advise that you teach students a strategy and practice it until they are good at it before adding another one. The last page contains a suggestions, according to CCSS of what grade levels need to be taught which strategies and which times.