If you’d like to supplement your curriculum with some challenging problems, there are many resources available.

The TOPS decks for early elementary Techniques of Problem Solving Level 2 to middle school Techniques of Problem Solving Level 8: Deck Bb are a terrific source of problems. See more about these in Top Picks for Home Learners.

For elementary and middle school students Creative Problem Solving in School Mathematics, Revised and Expanded 2nd Edition and Math Olympiad Contest Problems for Elementary and Middle Schools are good choices.

Books such as The Art Of Problem Solving: And Beyond and Introduction to Geometry are appropriate for advanced middle and high school students.