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.
$7 + 5$
$8 + 6$
$9 + 4$
$6 + 6$
$9 + 9$
$13 + 4$
$8 + 7$
$14 + 5$
$9 + 8$
$7 + 7 + 6$
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. If a child knows $7 + 5 = 12$, they already know $12 - 5$.
$12 - 5$
$15 - 8$
$18 - 9$
$14 - 6$
$20 - 7$
$16 - 9$
$13 - 8$
$19 - 4$
$17 - 9$
$20 - 11$
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. Left to right, not the way the written algorithm goes - it is easier to hold in your head.
$34 + 25$
$46 + 30$
$58 + 21$
$27 + 38$
$45 + 45$
$63 + 29$
$52 + 48$
$36 + 47$
$74 + 19$
$85 + 36$
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. To do $52 - 38$, count from 38 up to 52.
$50 - 24$
$63 - 28$
$80 - 35$
$47 - 19$
$91 - 46$
$72 - 38$
$100 - 64$
$85 - 27$
$66 - 39$
$74 - 48$
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. The 9s, for instance, always have digits that add to 9.
$6 \times 7$
$8 \times 8$
$9 \times 6$
$7 \times 9$
$12 \times 4$
$6 \times 8$
$11 \times 7$
$9 \times 9$
$8 \times 7$
$12 \times 12$
Answers for Times Tables
42, 64, 54, 63, 48, 48, 77, 81, 56, 144
Set 6 - Division Facts (Ages 8–10)
Division undoes multiplication. If $6 \times 7 = 42$, then $42 \div 7 = 6$. Same fact, asked from the other end.
$42 \div 6$
$56 \div 8$
$72 \div 9$
$63 \div 7$
$48 \div 6$
$81 \div 9$
$36 \div 4$
$96 \div 8$
$77 \div 11$
$144 \div 12$
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. The decimal does not "gain a zero" - the digits move. That distinction matters once decimals arrive.
$34 \times 10$
$7 \times 100$
$520 \div 10$
$2.5 \times 100$
$4600 \div 100$
$9 \times 1000$
$0.6 \times 10$
$8000 \div 1000$
$3.2 \times 10$
$750 \div 100$
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, and a percentage is just a fraction out of 100. Half, quarter, and tenth are the anchors - most mental fraction work bends back to those.
$\frac{1}{2}$ of $48$
$\frac{1}{4}$ of $60$
$\frac{3}{4}$ of $40$
$\frac{1}{2} + \frac{1}{4}$
$\frac{2}{3}$ of $30$
$0.5 + 0.25$
$\frac{1}{10}$ of $250$
$\frac{1}{2} - \frac{1}{3}$
$0.75 \times 8$
$\frac{3}{5}$ of $50$
Answers for Fractions And Decimals
24, 15, 30, $\frac{3}{4}$, 20, 0.75, 25, $\frac{1}{6}$, 6, 30
Set 9 - Percentages (Ages 11–13)
Find 10% first (move the decimal one place), then build the rest from it. 25% is half of 50%; 5% is half of 10%.
$10%$ of $80$
$50%$ of $46$
$25%$ of $200$
$20%$ of $150$
$5%$ of $60$
$15%$ of $40$
$30%$ of $90$
$75%$ of $80$
$1%$ of $700$
$40%$ 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. The arithmetic here is small; the work is reading the sentence and choosing the operation. That choice is where most marks are lost.
A pack holds 24 pencils. How many pencils are in 5 packs?
A film starts at 3:45 and runs 90 minutes. When does it end?
Three friends share ₹150 / $15 / £12 equally. How much each?
A book has 200 pages. You have read 60%. How many pages are left?
A train leaves at 09:20 and arrives at 11:05. How long is the journey?
Apples cost ₹8 / 80¢ / 70p each. What do 7 apples cost?
A rectangle is 12 cm long and 5 cm wide. What is its area?
You buy something for ₹240 / $24 / £19 and pay with ₹500 / $50 / £40. What is the change?
A recipe for 4 people needs 300 g of flour. How much for 6 people?
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 / $5 / £4 each, 80 pages left, 1 hour 45 minutes, ₹56 / $5.60 / £4.90, 60 cm², ₹260 / $26 / £21, 450 g, 5 cycle (15 don't walk, a third of 15 = 5)
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.
Here is the gap most worksheets miss. A child can get $52 - 38$ right with a written borrowing algorithm and still have no idea that the answer means "the distance from 38 to 52." A mental maths question removes the algorithm and exposes the understanding underneath. There is nowhere to hide a procedure you do not really get.
That is why these questions reward reasoning over recall:
They build number sense. Doing $63 + 29$ in your head as $63 + 30 - 1$ teaches a child that 29 is "almost 30." That instinct - rounding, adjusting, estimating - is the single most useful number skill there is.
They free up working memory. A child who has to count out $6 \times 7$ on their fingers during an algebra problem has no attention left for the algebra. Fast, calm recall of the basics is what makes harder math possible.
They surface gaps early. If a 10-year-old freezes on Set 6, the problem is usually not division - it is that the matching times-table fact in Set 5 never became automatic. Mental maths questions point straight at the real gap.
The honest version: tricks alone do not last. A child who memorizes "to multiply by 5, halve and times ten" without understanding why will forget it under pressure or misapply it. The reasoning is what survives. (More on the difference in our piece on what speed math actually is.)
Common Mistakes When Using A Mental Maths Question Bank
1. Treating it as a timed test from day one
Where it slips in:
A parent sets a stopwatch on the first attempt, the child panics, and the whole exercise becomes a source of dread.
The correct way:
Accuracy first, calm second, speed a distant third. Speed is a by-product of understanding, never the starting goal.
2. Skipping ahead because a child "knows" their tables
Where it slips in:
A confident child races to Set 9 percentages while Set 6 division is still shaky.
The correct way:
Percentages lean on division. If the lower set wobbles, the higher set collapses. Shore up the foundation first — the same diagnostic-first logic good math tutoring uses to find the true starting level.
3. Asking only for the answer
The rusher blurts a number and moves on. The silent understander knows the method but never says it. Both lose the most valuable part of the exercise. Ask "how?" not just "what?"
How Bhanzu Builds Mental Maths Skill
Bhanzu does not hand children a list of mental maths tricks to memorize. The approach starts the other way around: understand how numbers are structured, and the shortcuts fall out on their own.
Every learner begins at Level 0 - a diagnostic that finds the real gap, not the grade printed on a report card. A child who freezes on two-digit subtraction is not pushed forward; the gap is named and built up first.
From there, mental agility grows out of reasoning about number structure - the same patterns-not-memorizing stance that makes a times table feel obvious instead of arbitrary. That understanding transfers. A child who genuinely gets why $63 + 29$ becomes $63 + 30 - 1$ carries that adjusting instinct into algebra, where it shows up again as factoring and completing the square.
Conclusion
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. Start at the set that matches the learner, keep accuracy ahead of speed, and always ask how the answer was reached.
To take this further with a teacher, explore Bhanzu's mental maths for kids program or sit in on math classes online where trainers build this skill from the reasoning up.
Want your child to build calm, confident mental maths with a live trainer? Book a free demo class.
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