How To Use These Exercises
These mental math exercises are arranged in eight sets, beginner to advanced. Unlike a one-off quiz, they are designed to be repeated - the same set, several days running, until the answers come back fast and calm, then on to the next.
How to get real gains out of them:
Five minutes a day, not an hour a week. Number fluency is built by short, frequent reps. A daily streak of one set beats a long, draining Saturday session almost every time.
Track accuracy before speed. Write down how many you got right today. Only start timing yourself once a set is reliably all-correct. Chasing speed too early just trains guessing.
Repeat the set you fail. A set you score 6/10 on is not finished. Redo it tomorrow. Moving on with a wobbly foundation is how the advanced sets collapse later.
Do it in your head. The moment you reach for paper, the set is too hard - step back one level.
These exercises pair naturally with the worked methods in our mental math examples guide and the broader shortcuts in mental math tricks. Do the reading first, then drill here.
Set 1 — Number Bonds (Beginner)
Pairs that make 10 and 20. The bedrock of everything above.
$6 + 4$
$7 + 3$
$8 + ?\ = 10$
$9 + 9$
$5 + 8$
$15 + 5$
$13 + 7$
$6 + 7$
$20 - 6$
$10 - 4$
Set 2 — Adding And Subtracting To 50 (Beginner)
Tens first, then ones. Round-and-adjust where it helps.
$23 + 14$
$38 + 11$
$45 - 12$
$27 + 19$
$50 - 23$
$34 + 16$
$48 - 29$
$26 + 26$
$41 - 18$
$33 + 17$
Set 3 - Times Tables Mixed (Intermediate)
Pulled from across the tables, not in order — order is what makes them easy and recall is what you are building.
$7 \times 6$
$8 \times 9$
$6 \times 6$
$9 \times 7$
$12 \times 8$
$7 \times 7$
$11 \times 9$
$8 \times 6$
$9 \times 9$
$12 \times 6$
Set 4 - Division Facts (Intermediate)
The reverse of Set 3. If a fact here is slow, the matching multiplication fact is the gap.
$48 \div 6$
$63 \div 9$
$72 \div 8$
$54 \div 6$
$96 \div 8$
$77 \div 7$
$108 \div 9$
$84 \div 7$
$132 \div 12$
$45 \div 5$
Set 5 - Three-Digit Operations (Intermediate)
Split by place value. Compensate when a number is near a hundred.
$245 + 130$
$398 + 207$
$500 - 264$
$632 - 150$
$175 + 175$
$704 - 358$
$250 + 380$
$1000 - 472$
$460 + 290$
$815 - 199$
Set 6 - Fractions And Decimals (Advanced)
Anchor on halves, quarters, and tenths. Re-cut to a common size before adding.
$\frac{1}{2}$ of $86$
$\frac{3}{4}$ of $48$
$\frac{2}{5}$ of $60$
$\frac{1}{2} + \frac{1}{3}$
$\frac{5}{6} - \frac{1}{2}$
$0.25 + 0.5$
$0.75 \times 12$
$\frac{1}{10}$ of $340$
$\frac{2}{3}$ of $45$
$1 - \frac{3}{8}$
Set 7 - Percentages (Advanced)
Find 10% first, then build. 25% is half of 50%; 5% is half of 10%.
$10%$ of $90$
$25%$ of $160$
$15%$ of $80$
$50%$ of $74$
$20%$ of $250$
$5%$ of $120$
$30%$ of $60$
$75%$ of $40$
$12%$ of $50$
$40%$ of $300$
Set 8 - Two-Step Problems (Advanced)
The hardest set. Choose the operations, do them in order, hold the in-between number.
Buy 3 items at ₹45 / $4.50 / £3.60 each. Total?
$20%$ off a ₹250 / $25 / £20 item. Sale price?
A class of 40 is 60% girls. How many boys?
$7 \times 8$, then $+ 14$.
Half of 88, then double it.
A 90-minute film starts at 18:40. End time?
$\frac{3}{4}$ of 200, then $- 50$.
Share ₹360 / $36 / £30 among 4, then take 2 shares.
$15%$ of 200, then $\times 2$.
$144 \div 12$, then squared.
Why Mental Math Exercises Sharpen More Than Speed
Mental math exercises are not really about getting faster. They are about freeing up the part of your brain that the math needs later.
Think of working memory as a small desk. A child who has to slowly work out $7 \times 8$ during a long-division problem has used the whole desk on that one fact, with no room left for the division itself. Drill the fact until it is automatic, and the desk clears. That is the real payoff of these exercises - not party-trick speed, but headroom for harder math.
The exercises do three jobs at once:
They turn slow recall into automatic recall. A fact you compute is a fact still costing effort. A fact you know costs nothing. Repetition is what moves a fact from the first column to the second.
They expose the weak link. A learner who flies through Set 3 but stalls on Set 4 has a clear, named gap: the inverse direction. The exercises diagnose, not just drill.
They build estimation as a side effect. Doing $815 - 199$ by rounding 199 to 200 trains the habit of seeing roughly where an answer should land - which is how you catch a calculator typo or a careless slip.
One honest limit: drilling alone, without understanding, plateaus. A child who grinds Set 3 by rote but never sees the patterns in the tables will hit a wall the moment a problem looks unfamiliar. Pair the drilling with the reasoning.
Common Mistakes When Doing Mental Math Exercises
1. Chasing speed before accuracy is solid
Where it slips in:
A learner times every set from day one, the timer creates panic, and accuracy drops as speed becomes the only goal.
The correct way:
All-correct first, every session, for several days. Then - and only then - add the timer. Speed is the reward for accuracy, not a substitute for it.
2. Moving on after a single good session
Where it slips in:
A child scores 9/10 once and jumps to the next set, mistaking one good run for mastery.
The correct way:
A set is mastered when it is reliable across several days, not on its best day. The memorizer who crammed it once will lose it by next week; spaced repetition is what makes it stick.
3. Reaching for paper
The second a pencil comes out, the exercise stopped being mental math. If a set genuinely needs paper, it is a level too high - drop back, build the foundation, return.
A Four-Week Practice Plan
Use this as a starting frame and adjust to the learner's pace - there is no prize for rushing.
Week 1: Sets 1–2, one per day, alternating. Goal: all-correct, no finger-counting.
Week 2: Sets 3–4. Tables and their inverses, back to back, so the partnership is obvious.
Week 3: Set 5, then introduce Set 6. Three-digit work and fractions.
Week 4: Sets 7–8. Percentages and two-step problems. Now add a gentle timer to the earlier, mastered sets.
If a set refuses to stick, the plan is wrong, not the child - go back a set and rebuild. This diagnostic-then-build sequence is the same logic behind good math tutoring: find the real gap, fix it, then move forward.
How Bhanzu Builds This Skill
Bhanzu treats exercises as a way to find and close gaps, not as busywork. Every learner starts at Level 0 - a diagnostic that shows which sets are genuinely automatic and which only look solid — so practice targets the real weak link instead of grinding everything equally.
The deeper difference is what the drilling sits on. Bhanzu builds the understanding first - why $\times 5$ is $\times 10 \div 2$, why division undoes multiplication - so that when a learner drills, they are reinforcing reasoning, not memorizing in the dark. That is why the skill transfers. Mental agility grown from understanding number structure shows up later in algebra and beyond; a memorized set of facts only covers the exact cases it was drilled on.
Conclusion
Mental math exercises sharpen the mind by making the basics automatic, which clears room for the harder math that builds on them. Run them in short daily bursts, lock in accuracy before speed, and repeat any set that wobbles. The four-week plan above is a frame, not a race.
To build this skill with a teacher who diagnoses the real gap first, explore Bhanzu's mental maths for kids program or private math tutor sessions tuned to the learner.
Want a free diagnostic of where your child actually stands? Book a free demo class.
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Answers
Set 1: 1) 10 2) 10 3) 2 4) 18 5) 13 6) 20 7) 20 8) 13 9) 14 10) 6
Set 2: 1) 37 2) 49 3) 33 4) 46 5) 27 6) 50 7) 19 8) 52 9) 23 10) 50
Set 3: 1) 42 2) 72 3) 36 4) 63 5) 96 6) 49 7) 99 8) 48 9) 81 10) 72
Set 4: 1) 8 2) 7 3) 9 4) 9 5) 12 6) 11 7) 12 8) 12 9) 11 10) 9
Set 5: 1) 375 2) 605 3) 236 4) 482 5) 350 6) 346 7) 630 8) 528 9) 750 10) 616
Set 6: 1) 43 2) 36 3) 24 4) $\frac{5}{6}$ 5) $\frac{1}{3}$ 6) 0.75 7) 9 8) 34 9) 30 10) $\frac{5}{8}$
Set 7: 1) 9 2) 40 3) 12 4) 37 5) 50 6) 6 7) 18 8) 30 9) 6 10) 120
Set 8: 1) ₹135 / $13.50 / £10.80 2) ₹200 / $20 / £16 3) 16 boys 4) 70 5) 88 6) 20:10 7) 100 8) ₹180 / $18 / £15 9) 60 10) 144
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