Try a short, untimed round of number puzzles. Enter your answers to check them, or open each hint and worked explanation. Start with reasoning; speed can wait.
These are original website practice questions, not app levels or a preview of the app interface. Nothing is saved or sent to Moocsoft. The free web challenge is separate from Math Riddles, which has ads and optional in-app purchases.
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.
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 five original web exercises. 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. Editing an answer clears its previous check; refreshing or resetting clears the round. Opening an explanation does not count as a correct answer. This is practice, not an IQ test or a claim about cognitive improvement.