Math Riddles
100 Math Riddles with Answers | Fun & Tricky Brain Teasers for All Ages
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1. What three numbers give the same result when added and multiplied?
Answer: 1, 2, and 3

2. If two’s company and three’s a crowd, what are four and five?
Answer: Nine

3. I am an odd number. Take away one letter and I become even. What number am I?
Answer: Seven

4. How many times can you subtract 10 from 100?
Answer: Once — after that, you’re subtracting from 90.

5. If 5 cats can catch 5 mice in 5 minutes, how many cats are needed to catch 100 mice in 100 minutes?
Answer: 5 cats

6. What is half of two plus two?
Answer: Three

7. If you multiply me by any number, the answer will always remain the same. What number am I?
Answer: Zero

8. A farmer has 17 sheep, and all but 9 run away. How many are left?
Answer: 9

9. If 3 kids can eat 3 pizzas in 3 minutes, how many pizzas can 6 kids eat in 6 minutes?
Answer: 12 pizzas

10. What comes after one thousand and before one thousand two?
Answer: 1001

11. A clock strikes once at 1 o’clock, twice at 2 o’clock, and so on. How many times will it strike in 12 hours?
Answer: 78 times

12. Using only addition, how do you add eight 8’s to get 1,000?
Answer: 888 + 88 + 8 + 8 + 8 = 1,000

13. What number do you get when you multiply all the numbers on a telephone keypad?
Answer: Zero

14. What two whole numbers are closest to the square root of 50?
Answer: 7 and 8

15. I am a three-digit number. My tens digit is five more than my ones digit, and my hundreds digit is eight less than my tens digit. What number am I?
Answer: 194

16. A bat and a ball cost $1.10 in total. The bat costs $1 more than the ball. How much does the ball cost?
Answer: 5 cents

17. Divide 30 by half and add 10. What’s the answer?
Answer: 70

18. What number becomes smaller when you turn it upside down?
Answer: 9

19. If there are 4 apples and you take away 3, how many do you have?
Answer: 3 (because you took them)

20. How many sides does a circle have?
Answer: Two — inside and outside

21. A triangle has sides of 3, 4, and 5. What kind of triangle is it?
Answer: Right triangle

22. What’s the next number in the pattern: 2, 6, 12, 20, 30, …?
Answer: 42

23. How can you make 6 from three 3’s?
Answer: (3 + 3) = 6 or (3 * 3) / 1.5 = 6

24. If there are six eggs in a basket and six people each take one, how can one egg still be left?
Answer: The last person took the basket with the egg inside.

25. What has a face and hands but no arms or legs?
Answer: A Clock


🔹 Challenging Math Riddles (26–50)

26. How many months have 28 days?
Answer: All 12 months

27. If it takes 10 minutes to hard-boil one egg, how long to boil three eggs?
Answer: 10 minutes (they can be boiled together)

28. I am a number. Multiply me by 3, add 12, divide by 6, and you get 7. What number am I?
Answer: 10

29. A man bought a horse for $60 and sold it for $70. Then he bought it again for $80 and sold it for $90. How much profit did he make?
Answer: $20

30. How many seconds are there in a year?
Answer: 12 (January 2nd, February 2nd, etc.)

31. What two numbers, when multiplied, give 36 and when added, give 13?
Answer: 9 and 4

32. How many 2-cent stamps are there in a dozen?
Answer: 12

33. What is the sum of all numbers from 1 to 100?
Answer: 5,050

34. What is always between 7 and 8?
Answer: The decimal point

35. How can you make the number 7 even?
Answer: Remove the “S”

36. If you have three apples and you take away two, how many apples do you have?
Answer: 2

37. Which weighs more — a pound of feathers or a pound of bricks?
Answer: They weigh the same

38. What number is the Roman numeral for 1000?
Answer: M

39. If you double a number and add 10, you get 30. What’s the number?
Answer: 10

40. How many legs do two dogs and a chicken have together?
Answer: 10

41. What is 25% of 200?
Answer: 50

42. If 1 = 3, 2 = 3, 3 = 5, 4 = 4, and 5 = 4, what is 6?
Answer: 3 (because “six” has three letters)

43. How many zeros are there in one thousand?
Answer: Three

44. If 11 + 2 = 1, what does 9 + 5 equal?
Answer: 2 (clock math)

45. A man adds 100 and 100 but gets 2001. How?
Answer: He added 100 and 100 on paper, side by side (1001001)

46. What’s half of 12 and twice of 3 at the same time?
Answer: 6

47. I am a number less than 100, and the sum of my digits equals 9. If you reverse my digits, I am 27 more. What number am I?
Answer: 36

48. Which number is missing: 3, 6, 9, 12, __, 18?
Answer: 15

49. How many times can you subtract 2 from 20?
Answer: Once

50. How many sides does a rectangle have?
Answer: 4

🔹 Tricky Math Riddles (51–75)

51. If five cats can catch five mice in five minutes, how long will it take one cat to catch one mouse?
Answer: Five minutes

52. What two numbers make 10 when multiplied and 7 when added?
Answer: 5 and 2

53. You buy a dozen eggs for $1.20. How much does one egg cost?
Answer: $0.10

54. How many times can you subtract 1 from 10?
Answer: Once

55. What number do you get when you multiply all the digits on a calculator?
Answer: 0

56. If there are four apples and you take away three, how many do you have?
Answer: 3

57. What’s 3/7 chicken, 2/3 cat, and 2/4 goat?
Answer: Chicago

58. Add me to myself and multiply by 4. Divide me by 8 and you’ll find me again. What number am I?
Answer: Any number

59. Which number, when multiplied by itself, gives the same result as when it is added to itself?
Answer: 2

60. If you multiply this number by any other number, the answer will always be the same. What number am I?
Answer: 0

61. You have 10 fingers. How many fingers are there on 10 hands?
Answer: 50

62. A snail climbs 3 feet each day and slips back 2 feet at night. How many days will it take to climb a 10-foot wall?
Answer: 8 days

63. If two hours ago, it was as long after one o’clock as it was before one o’clock yesterday, what time is it now?
Answer: 9:00 PM

64. Multiply me by 4, divide me by 2, and add 10 — you’ll still get me. What number am I?
Answer: 10

65. What number do you get when you add all the numbers from 1 to 10?
Answer: 55

66. You have 100 coins, and 10 are heads. How do you make two piles with an equal number of heads?
Answer: Take 10 coins and flip them — both piles will have the same number of heads.

67. What is always in front of you but can’t be seen and can change your numbers instantly?
Answer: The Future

68. How many sides does a hexagon have?
Answer: Six

69. Which number is twice the sum of its digits?
Answer: 18

70. If 9x = 81, what is x?
Answer: 9

71. What can be added to 8 to make it disappear?
Answer: The letter “S” (makes “eight” → “sight”)

72. What number increases and decreases but always stays the same?
Answer: Your Age (as years pass, it increases, but your birth year stays the same)

73. I’m an even number. Take away a letter and I become odd. What number am I?
Answer: Seven

74. What has 4 legs in the morning, 2 at noon, and 3 at night?
Answer: A Human

75. What can you divide by itself and still get itself?
Answer: 1


🔹 Expert Math Riddles (76–100)

76. I’m thinking of a number. Double it and add 10, then halve it, and you’ll get 15. What’s the number?
Answer: 10

77. What is the next number? 1, 11, 21, 1211, 111221, …
Answer: 312211

78. If 6 children can eat 6 slices of pizza in 6 minutes, how long will 12 children take to eat 12 slices?
Answer: 6 minutes

79. What two numbers add up to 10 and multiply to 21?
Answer: No whole numbers (solution: 7 and 3 are close, but 7×3=21, 7+3=10 ✅)

80. What is 1 + 4 = 5, 2 + 5 = 12, 3 + 6 = 21, 8 + 11 = ?
Answer: 96 (pattern: multiply and add first number)

81. How can you make 1000 using eight 8’s?
Answer: 888 + 88 + 8 + 8 + 8 = 1000

82. What number when spelled out has letters in alphabetical order?
Answer: Forty

83. What number when multiplied by itself gives you the same number?
Answer: 1

84. What’s the largest single-digit prime number?
Answer: 7

85. Which number is missing? 2, 3, 5, 9, 17, 33, __?
Answer: 65 (pattern: double and add 1)

86. What number do you get when you multiply 111 by 111?
Answer: 12,321

87. What number is equal to half of one dozen?
Answer: 6

88. How many degrees are there in a triangle?
Answer: 180

89. If you triple me and subtract 6, you get 9. What am I?
Answer: 5

90. What is the square root of 81?
Answer: 9

91. How many sides does a cube have?
Answer: 6

92. What is the perimeter of a square with sides of 5 cm?
Answer: 20 cm

93. If you have a dozen apples and eat three, how many are left?
Answer: 9

94. What is 15% of 200?
Answer: 30

95. What’s the next number: 2, 4, 8, 16, 32, …?
Answer: 64

96. What number do you get if you divide 100 by 5 and then by 2?
Answer: 10

97. What’s the sum of the angles in a square?
Answer: 360°

98. If 2x + 3 = 11, what is x?
Answer: 4

99. What is ¾ of 20?
Answer: 15

100. What two numbers multiply to 16 and add to 10?
Answer: 2 and 8