Train your brain, one clever problem at a time

Original competition & Olympiad-style problems for every grade. Each task teaches a named abstract-thinking strategy — the same reasoning skills the SAT and math competitions reward. Pick your grade:

Grade 1 · 2 · 3 · 4 · 5 · 6 · 7 · 8 · 9 · 10 · 11 · 12

Every puzzle has its own page

Browse without the app: each grade has a page with all its puzzles, hints and solutions, and every puzzle has its own page to share or print.

Grade 1 · 12 puzzles

All grade 1 puzzles on one page

  1. Puzzle 1: Spot and count repeating groups
  2. Puzzle 2: Act it out step by step
  3. Puzzle 3: Draw a picture
  4. Puzzle 4: Order by comparing (transitivity)
  5. Puzzle 5: Check every possible case
  6. Puzzle 6: Guess and check smartly
  7. Puzzle 7: Simulate — and watch the ending
  8. Puzzle 8: Sort into cases and check a limit
  9. Puzzle 9: Track two patterns at once
  10. Puzzle 10: Track neighboring pairs
  11. Puzzle 11: Working backwards
  12. Puzzle 12: Symmetry
Grade 2 · 12 puzzles

All grade 2 puzzles on one page

  1. Puzzle 1: Count both ends in two groups
  2. Puzzle 2: Multiplication with equal groups
  3. Puzzle 3: Do the experiment in your head
  4. Puzzle 4: Connect ages across a timeline
  5. Puzzle 5: Swap and cancel on balances
  6. Puzzle 6: Compare two landing trails
  7. Puzzle 7: Beware of double counting
  8. Puzzle 8: Find the rate first
  9. Puzzle 9: Infer and test an addition rule
  10. Puzzle 10: Check two conditions
  11. Puzzle 11: Working backwards
  12. Puzzle 12: Extreme cases
Grade 3 · 12 puzzles

All grade 3 puzzles on one page

  1. Puzzle 1: Build greedily, digit by digit
  2. Puzzle 2: Bridge through a round number
  3. Puzzle 3: Compare two orders using a shared starting point
  4. Puzzle 4: Label with a letter (early algebra)
  5. Puzzle 5: Work backwards
  6. Puzzle 6: Systematic listing
  7. Puzzle 7: Bounding an extreme by ordering
  8. Puzzle 8: Eliminate using odd and even numbers
  9. Puzzle 9: Find the missing change
  10. Puzzle 10: Count in separate cases
  11. Puzzle 11: Parity
  12. Puzzle 12: Symmetry (mirror pairs)
Grade 4 · 12 puzzles

All grade 4 puzzles on one page

  1. Puzzle 1: Compare two expressions by their differences
  2. Puzzle 2: Pieces vs. cuts
  3. Puzzle 3: Combine moves, then discard full laps
  4. Puzzle 4: List factor pairs, then test
  5. Puzzle 5: Restore a missing area
  6. Puzzle 6: Count the gaps, not the posts
  7. Puzzle 7: Start from the extreme
  8. Puzzle 8: Count digit occurrences by position
  9. Puzzle 9: Test a pattern against examples and counterexamples
  10. Puzzle 10: Find and add gaps to a common total
  11. Puzzle 11: Pigeonhole principle
  12. Puzzle 12: Invariants
Grade 5 · 12 puzzles

All grade 5 puzzles on one page

  1. Puzzle 1: Compare to a benchmark
  2. Puzzle 2: Compare two division sentences
  3. Puzzle 3: Count shared endpoints and gaps
  4. Puzzle 4: Count overlapping groups using totals
  5. Puzzle 5: Sort by position, then count
  6. Puzzle 6: Use place-value structure
  7. Puzzle 7: Track two piles backward
  8. Puzzle 8: Block-swap pairing with a leading-zero check
  9. Puzzle 9: Increasing-step pattern
  10. Puzzle 10: Equal grouping from chart totals
  11. Puzzle 11: Extreme cases
  12. Puzzle 12: Parity
Grade 6 · 12 puzzles

All grade 6 puzzles on one page

  1. Puzzle 1: See percents as fractions
  2. Puzzle 2: Move along the number line
  3. Puzzle 3: Halfway = average
  4. Puzzle 4: Compare shares of an unchanged total
  5. Puzzle 5: The middle is the average
  6. Puzzle 6: Test with easy numbers
  7. Puzzle 7: Filter square roots using remainders
  8. Puzzle 8: Assume and find a contradiction
  9. Puzzle 9: Reasoning with digit place values
  10. Puzzle 10: Compare pair averages using totals
  11. Puzzle 11: Symmetry
  12. Puzzle 12: Invariant (conserved cubes)
Grade 7 · 12 puzzles

All grade 7 puzzles on one page

  1. Puzzle 1: Undo a repeated routine in reverse
  2. Puzzle 2: Find a last-digit cycle
  3. Puzzle 3: Use a full-turn invariant
  4. Puzzle 4: Percents multiply, not add
  5. Puzzle 5: Build a count, then correct for overlap
  6. Puzzle 6: Total distance ÷ total time
  7. Puzzle 7: Count guaranteed prime factors
  8. Puzzle 8: Count unordered groups by dividing out their orders
  9. Puzzle 9: Find and verify a two-term recursive pattern
  10. Puzzle 10: Compare signed triangular areas
  11. Puzzle 11: Bound with neighboring pairs
  12. Puzzle 12: Pigeonhole principle
Grade 8 · 12 puzzles

All grade 8 puzzles on one page

  1. Puzzle 1: Split side lengths around their midpoint
  2. Puzzle 2: Recognize structure (triples)
  3. Puzzle 3: Use a common power for squares and cubes
  4. Puzzle 4: Relate proportional rise and run
  5. Puzzle 5: Use a shared root and factor pairs
  6. Puzzle 6: Count arrangements and ties
  7. Puzzle 7: Track prime exponents
  8. Puzzle 8: Checkerboard coloring and construction
  9. Puzzle 9: Count two interleaved sequences
  10. Puzzle 10: Extremal reasoning with reordered increases
  11. Puzzle 11: Counting the complement
  12. Puzzle 12: Double counting
Grade 9 · 12 puzzles

All grade 9 puzzles on one page

  1. Puzzle 1: Check zero factors before canceling
  2. Puzzle 2: Compare trips to find a unit rate
  3. Puzzle 3: Cancel even terms at opposite inputs
  4. Puzzle 4: Concurrency with a distinctness check
  5. Puzzle 5: Factor to find a remainder
  6. Puzzle 6: Factor a difference of squares
  7. Puzzle 7: Factor a difference of squares and count symmetric solutions
  8. Puzzle 8: Link symmetric expressions through identities
  9. Puzzle 9: Place-value equations and divisibility
  10. Puzzle 10: Balance a product
  11. Puzzle 11: Count by blocks and gaps
  12. Puzzle 12: Pairing odd-degree vertices
Grade 10 · 12 puzzles

All grade 10 puzzles on one page

  1. Puzzle 1: Complete the square
  2. Puzzle 2: Compare linear and quadratic scaling
  3. Puzzle 3: Convert an area ratio into a length ratio
  4. Puzzle 4: Choose a perpendicular direction using a half-plane
  5. Puzzle 5: Cofunction pairing and double-angle identity
  6. Puzzle 6: Double counting in a triangulation
  7. Puzzle 7: Parity of prime factors in divisor counts
  8. Puzzle 8: Track two interacting cycles
  9. Puzzle 9: Recognize alternating ratios and compare prime exponents
  10. Puzzle 10: Weighted conditional probability
  11. Puzzle 11: Permutation parity via inversions
  12. Puzzle 12: Exchange argument
Grade 11 · 12 puzzles

All grade 11 puzzles on one page

  1. Puzzle 1: Use equal spacing to recover exponential growth
  2. Puzzle 2: Translate logarithms into exponents
  3. Puzzle 3: Quadratic finite differences
  4. Puzzle 4: Compare discriminants and count distinct roots
  5. Puzzle 5: Geometric series with overlapping sets
  6. Puzzle 6: Complete the random order and use symmetry
  7. Puzzle 7: Inclusion–exclusion with rotational symmetry
  8. Puzzle 8: Bridge between symmetric identities and an attainable bound
  9. Puzzle 9: Factor an integer polynomial using known roots
  10. Puzzle 10: Combine modular cycles with exponent divisibility
  11. Puzzle 11: Find a grouped parity invariant
  12. Puzzle 12: Coordinate normalization
Grade 12 · 12 puzzles

All grade 12 puzzles on one page

  1. Puzzle 1: Compare squares to reveal a complex number’s real part
  2. Puzzle 2: Track a composition around a cycle
  3. Puzzle 3: Use a zero-sum identity for cyclic differences
  4. Puzzle 4: Split into regions, then verify roots
  5. Puzzle 5: Symmetrize reciprocal log products
  6. Puzzle 6: Count cyclic arrangements using gaps and rotational symmetry
  7. Puzzle 7: Pell-equation descent
  8. Puzzle 8: Polynomial reduction and interpolation
  9. Puzzle 9: Classify with modular arithmetic
  10. Puzzle 10: Conditional counting by cases
  11. Puzzle 11: Binary factorization modulo 2
  12. Puzzle 12: Unfolding by reflection

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