Choose mixed riddles, everyday numbers or a logic break. Every question has a hint and worked solution. Check one round, send its link to a friend, or return for a different set. No timer, account or saved score.
These are original website practice questions, not app levels or a preview of the app interface. Your answers stay in this page and are not sent to Moocsoft or stored between visits. The free web challenge is separate from Math Riddles, which has ads and optional in-app purchases.
Practise operations, a stated row rule, digits, fractions and grid counting.
Choose a different round ↑What is 9 + 4 × (8 − 5)?
Calculate the brackets first. Multiplication comes before the final addition.
Answer: 21. 8 − 5 = 3. Then 4 × 3 = 12, and 9 + 12 = 21. Adding 9 and 4 first would change the expression.
Practise order of operations →Every row uses first × second + first. The examples are 3, 4 → 15 and 5, 6 → 35. What is the result for 7, 8?
Apply the stated rule to the final pair, not to the preceding result.
Answer: 63. The stated rule gives 7 × 8 + 7 = 56 + 7 = 63. It also checks both examples: 3 × 4 + 3 = 15 and 5 × 6 + 5 = 35. Giving the rule prevents several invented patterns from fitting a short list.
Try more missing-number puzzles →I am a two-digit positive whole number. My digits add to 13. Reversing them produces a number 27 greater than me. What number am I?
The units digit must be larger. Reversing two digits changes the number by nine times their difference.
Answer: 58. Let the tens digit be a and the units digit be b. The difference is (10b + a) − (10a + b) = 9(b − a). Therefore b − a = 3. Together with a + b = 13, this gives a = 5 and b = 8. The number is 58: 85 − 58 = 27.
Build a puzzle-solving checklist →Fill the missing numerator: ? / 12 = 5 / 6. Enter the numerator only.
The denominator doubles from 6 to 12. Apply the same change to the numerator.
Answer: 10. Multiply both parts of 5/6 by 2: 5 × 2 = 10 and 6 × 2 = 12. Thus 10/12 equals 5/6. As a second check, 10 × 6 and 5 × 12 both equal 60.
Compare fractions without decimals →A grid has 2 rows and 3 columns of equal square cells. How many rectangles of all sizes have sides on its grid lines? Include squares as rectangles; do not count tilted shapes.
A rectangle is determined by choosing two horizontal grid lines and two vertical grid lines.
Answer: 18. There are 3 horizontal grid lines, giving 3 possible pairs, and 4 vertical grid lines, giving 6 possible pairs. Each combination makes one rectangle, so 3 × 6 = 18. Counting by size gives the same total: 6 + 4 + 2 one-row rectangles and 3 + 2 + 1 two-row rectangles.
See the grid formula and more counting puzzles →Use each worked explanation to check your answer. Your work is not saved.
Share the round, not your answers. There is no multiplayer match or saved score on this website.
Open the Mixed reasoning link →Work through five fictional shopping, time, supplies, percentage and ratio problems.
Choose a different round ↑In a fictional shop, a notebook costs $3. You buy 4 notebooks and pay with $20. There are no taxes or extra charges. How many dollars should you receive in change? Enter the dollar amount as a whole number.
Find the cost of all four notebooks before subtracting it from the payment.
Answer: 8. Four notebooks cost 4 × 3 = 12 dollars. The change is 20 − 12 = 8 dollars. Checking in the other direction, 12 + 8 = 20. These are fictional prices, not a current shopping offer.
Practise grouping a calculation →A fictional study session starts at 18:35 and ends at 20:10 on the same evening. There are no clock changes or breaks. How many minutes does it last?
Count from 18:35 to 19:00, then to 20:00, then to 20:10.
Answer: 95. There are 25 minutes from 18:35 to 19:00, 60 more to 20:00 and 10 more to 20:10. The total is 25 + 60 + 10 = 95 minutes, or 1 hour 35 minutes. A second check is (20 × 60 + 10) − (18 × 60 + 35) = 95.
Compare two elapsed-time methods →A fictional club opens 6 packs containing exactly 8 pencils each. It gives away 17 pencils and loses none. How many pencils remain?
Calculate how many pencils were in the six packs, then subtract only the pencils given away.
Answer: 31. The packs contain 6 × 8 = 48 pencils. After 17 are given away, 48 − 17 = 31 remain. The check 31 + 17 = 48 accounts for every pencil.
Practise mental multiplication →A fictional club has exactly 64 members. Exactly 25% of them choose the morning meeting. How many members choose it?
Twenty-five percent is one quarter. Divide the total into four equal groups.
Answer: 16. 25% = 25/100 = 1/4. Therefore 64 ÷ 4 = 16 members choose the morning meeting. Checking the percentage gives 16 × 100 ÷ 64 = 25%.
Practise reasoning with fractions →In a fictional arithmetic exercise, blue and white paint are mixed in a ratio of 2:3 by volume. The total is 35 cups, with no loss of volume. How many cups are white paint? This is a number exercise, not paint-mixing advice.
The total contains five equal ratio parts. Find the size of one part, then take three parts.
Answer: 21. There are 2 + 3 = 5 equal parts in all. Each part is 35 ÷ 5 = 7 cups. White paint uses 3 × 7 = 21 cups; blue uses 2 × 7 = 14 cups. The checks are 14 + 21 = 35 and 14:21 = 2:3.
Check equal proportions with fractions →Use each worked explanation to check your answer. Your work is not saved.
Share the round, not your answers. There is no multiplayer match or saved score on this website.
Open the Everyday numbers link →Use explicit number, digit, pairing and remainder constraints to find one answer per puzzle.
Choose a different round ↑Which prime number is greater than 40 and less than 50, and has digits that add to 11?
List the integers in the stated range. Use the digit-sum clue, then verify that the remaining number is prime.
Answer: 47. A number in this range has tens digit 4, so its units digit must be 7 to make 4 + 7 = 11. The candidate is 47. To check that it is prime, test the primes no greater than its square root: 2, 3 and 5 do not divide 47. Therefore 47 satisfies both clues.
Use a prime-number checklist →Two positive whole numbers add to 29. The larger number is exactly 7 greater than the smaller number. What is the larger number?
Remove the difference from the total. The amount left is twice the smaller number.
Answer: 18. Subtract the difference: 29 − 7 = 22. That leaves two copies of the smaller number, so the smaller number is 22 ÷ 2 = 11. The larger is 11 + 7 = 18. Both clues check: 18 + 11 = 29 and 18 − 11 = 7.
Turn clues into a solving checklist →Eight players take part in a fictional singles tournament. Every pair of different players plays exactly one match. There are no return matches or self-matches. How many matches are needed?
Each player has seven opponents, but multiplying 8 by 7 counts each match twice.
Answer: 28. There are 8 × 7 = 56 player-opponent counts. Each actual match appears twice, once from each player’s perspective. Divide by 2 to get 28 matches. Counting only new opponents gives the same result: 7 + 6 + 5 + 4 + 3 + 2 + 1 = 28.
See how round-robin pair counting works →Use the digit cards 1, 2 and 3 exactly once each to form a three-digit number. The number must be greater than 200, its hundreds digit must be odd, and its tens digit must be smaller than its units digit. What number satisfies every clue?
Use the first two clues to fix the hundreds digit. Then decide which order the remaining digits must take.
Answer: 312. The hundreds digit cannot be 1 because the number must exceed 200, and it cannot be 2 because it must be odd. It is therefore 3. The remaining digits are 1 and 2; the tens digit must be smaller, so they go in that order. The number is 312.
Practise eliminating options with clues →A whole number is greater than 10 and less than 30. Dividing it by 4 leaves a remainder of 1, and dividing it by 6 leaves a remainder of 3. What is the number?
List the numbers in the range that leave remainder 1 after division by 4. Test those candidates against the other clue.
Answer: 21. The first clue gives 13, 17, 21, 25 and 29. Dividing these by 6 leaves remainders 1, 5, 3, 1 and 5 respectively. Only 21 leaves remainder 3. Direct checks are 21 = 4 × 5 + 1 and 21 = 6 × 3 + 3.
Check every constraint before choosing an answer →Use each worked explanation to check your answer. Your work is not saved.
Share the round, not your answers. There is no multiplayer match or saved score on this website.
Open the Logic break link →Explore the separate app’s handcrafted riddles, hints and solutions, or challenge a friend in live 1v1. Available on iPhone, iPad and Android.
Free to download · Ads and optional in-app purchases. Check your store for current features and access.Make one attempt before opening a hint. Write the rule or calculation that led to your answer. If you get stuck, use the hint and try again; the explanation is there to make the reasoning visible, not to grade you.
Yes, under the stated rules. The row puzzle supplies its formula, the digit puzzle has two constraints, and the grid question defines which rectangles count. Short number patterns without those constraints can support more than one constructed rule.
No. This page contains 15 original web exercises in three five-question rounds. The mobile app has its own content and modes, including hints, solutions and live 1v1. See the store listing for current platform features and purchases.
No. Answer checks only run in this page, separately for each round. Editing an answer clears its previous check; refreshing clears all checks, and each reset clears only its own round. Opening an explanation does not count as a correct answer. The copy button copies only a public round link, never your answers or score. This is practice, not an IQ test or a claim about cognitive improvement.
Math Riddles combines a solo puzzle journey, quick brain games, hints and solutions with live 1v1 matches and private rooms for friends. Practise at your own pace, then test the same reasoning in a short head-to-head round.
Three useful starting points, chosen for this app. The full reading list is one click away.
Solve an original café logic-grid mystery with four clues, a blank worksheet, optional hints and a fully explained answer. No guessing or sign-up needed.
Solve the puzzle Math puzzlesTry five original missing-number puzzles with explained answers. Print the free question sheet and a separate answer key, or practise directly in your browser.
Read the guide Math puzzlesSet up a fair math-game challenge with shared questions, short rounds and a useful rematch review, then invite a friend to a private 1v1 room.
Read the guide