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100 Mental Maths Questions With Answers (Graded)

TL;DR
Mental maths questions are short problems solved in your head, without paper or a calculator - and the 100 below are graded by operation and level so a learner can start where they actually are. They run from single-digit addition through times tables, division, fractions, percentages, and word problems, with a full Answers section at the end. Use them as five-minute warm-ups, not a sit-down test.

How To Use This Question Bank

These 100 mental maths questions are sorted into ten sets of ten. Each set names its operation and the level it suits, so you are not handing a 7-year-old a percentage problem on day one. Read the set header, pick the one that matches the learner, and stay there until the answers come back fast and calm.

A few ground rules that make the bank work:

• No pencil, no calculator. The whole point of a mental maths question is that the working happens in the head. If a child reaches for paper, the question was a level too high - drop back a set.

• Speed comes last. First the answer is right. Then it is right without counting on fingers. Only then does it get faster. Rushing a child to speed before the reasoning is solid just trains guessing.

• Say the method out loud. Ask "how did you get that?" more often than "what's the answer?" The method is the thing you are actually building.

• Five minutes beats fifty. A short daily set holds far more than a long weekly grind. Most of the gain we see in learners comes from the small, repeated moments, not the marathon.

The sets move from easiest to hardest. Sets 1–4 suit roughly ages 6–9, Sets 5–7 suit ages 9–11, and Sets 8–10 reach into ages 11–13. Treat those bands loosely - a confident 8-year-old can run ahead, and there is no shame in an older learner shoring up the early sets first. If you want the reasoning behind each shortcut rather than just the drills, the companion piece on mental math tricks walks through why each one works.

Set 1 - Addition Within 20 (Ages 6–7)

These build number bonds - the pairs that make 10 and 20. Get these automatic and everything above gets easier.

1. 7+5
2. 8+6
3. 9+4
4. 6+6
5. 9+9
6. 13+4
7. 8+7
8. 14+5
9. 9+8
10. 7+7

Answers for Addition Within 20

12, 14, 13, 12, 18, 17, 15, 19, 17, 20

Set 2 - Subtraction Within 20 (Ages 6–7)

Subtraction is just addition seen backwards.

11. 12−5
12. 15−8
13. 18−9
14. 14−6
15. 20−7
16. 16−9
17. 13−8
18. 19−4
19. 17−9
20. 20−11

Answers for Subtraction Within 20

7, 7, 9, 8, 13, 7, 5, 15, 8, 9

Set 3 - Two-Digit Addition (Ages 7–9)

Add the tens first, then the ones.

21. 34+25
22. 46+30
23. 58+21
24. 27+38
25. 45+45
26. 63+29
27. 52+48
28. 36+47
29. 74+19
30. 85+36

Answers for Two-Digit Addition

59, 76, 79, 65, 90, 92, 100, 83, 93, 121

Set 4 - Two-Digit Subtraction (Ages 7–9)

Counting up from the smaller number is often calmer than borrowing.

31. 50−24
32. 63−28
33. 80−35
34. 47−19
35. 91−46
36. 72−38
37. 100−64
38. 85−27
39. 66−39
40. 74−48

Answers for Two-Digit Subtraction

26, 35, 45, 28, 45, 34, 36, 58, 27, 26

Set 5 - Times Tables (Ages 8–10)

Tables are patterns, not a wall of facts to memorize.

41. 6×7
42. 8×8
43. 9×6
44. 7×9
45. 12×4
46. 6×8
47. 11×7
48. 9×9
49. 8×7
50. 12×12

Answers for Times Tables

42, 64, 54, 63, 48, 48, 77, 81, 56, 144

Set 6 - Division Facts (Ages 8–10)

Division undoes multiplication.

51. 42÷6
52. 56÷8
53. 72÷9
54. 63÷7
55. 48÷6
56. 81÷9
57. 36÷4
58. 96÷8
59. 77÷11
60. 144÷12

Answers for Division Facts

7, 7, 8, 9, 8, 9, 9, 12, 7, 12

Set 7 - Multiply And Divide By 10, 100, 1000 (Ages 9–11)

Multiplying by 10 shifts every digit one place left.

61. 34×10
62. 7×100
63. 520÷10
64. 2.5×100
65. 4600÷100
66. 9×1000
67. 0.6×10
68. 8000÷1000
69. 3.2×10
70. 750÷100

Answers for Multiply And Divide By 10, 100, 1000

340, 700, 52, 250, 46, 9000, 6, 8, 32, 7.5

Set 8 - Fractions And Decimals (Ages 10–12)

A fraction is a part of a whole.

71. 12\frac{1}{2} of 48
72. 14\frac{1}{4} of 60
73. 34\frac{3}{4} of 40
74. 12+14\frac{1}{2}+\frac{1}{4}
75. 23\frac{2}{3} of 30
76. 0.5+0.25
77. 110\frac{1}{10} of 250
78. 12−13\frac{1}{2}−\frac{1}{3}
79. 0.75×8
80. 35\frac{3}{5} of 50

Answers for Fractions And Decimals

24, 15, 30, 34\frac{3}{4}, 20, 0.75, 25, 16\frac{1}{6}, 6, 30

Set 9 - Percentages (Ages 11–13)

Find 10% first, then build the rest from it.

81. 10% of 80
82. 50% of 46
83. 25% of 200
84. 20% of 150
85. 5% of 60
86. 15% of 40
87. 30% of 90
88. 75% of 80
89. 1% of 700
90. 40% of 250

Answers for Percentages

8, 23, 50, 30, 3, 6, 27, 60, 7, 100

Set 10 - Word Problems (Ages 11–13)

The last and hardest set.

91. A pack holds 24 pencils. How many pencils are in 5 packs?
92. A film starts at 3:45 and runs 90 minutes. When does it end?
93. Three friends share ₹150 equally. How much each?
94. A book has 200 pages. You have read 60%. How many pages are left?
95. A train leaves at 09:20 and arrives at 11:05. How long is the journey?
96. Apples cost ₹8 each. What do 7 apples cost?
97. A rectangle is 12 cm long and 5 cm wide. What is its area?
98. You buy something for ₹240 and pay with ₹500. What is the change?
99. A recipe for 4 people needs 300 g of flour. How much for 6 people?
100. Half the 30 students in a class walk to school. A third of the rest cycle. How many cycle?

Answers for Word Problems

120 pencils, 5:15, ₹50 each, 80 pages left, 1 hour 45 minutes, ₹56 each, 60 cm², ₹260, 450 g, 5 cycle

Why Mental Maths Questions Matter More Than They Look

Mental maths questions are not about being a human calculator. They are about whether a child understands what the numbers are doing.

That is the gap most worksheets miss. A mental maths question removes the algorithm and exposes the understanding underneath. There is nowhere to hide a procedure you do not really get.

• They build number sense.
• They free up working memory.
• They surface gaps early.

The honest version: tricks alone do not last. A child who memorizes methods without understanding will forget it under pressure or misapply it.

Common Mistakes When Using A Mental Maths Question Bank

1. Treating it as a timed test from day one

Correct way: Accuracy first, calm second, speed a distant third.

2. Skipping ahead because a child knows their tables

Correct way: Shore up the foundation first.

3. Asking only for the answer

Correct way: Ask "how?" not just "what?"

How Bhanzu Builds Mental Maths Skill

A good mental maths question bank is not a test to survive — it is a daily five-minute habit that builds the number sense everything else in math rests on.