Multiplication tricks for faster calculation: 12 useful methods

The best multiplication tricks for faster calculation do not make you calculate the same difficult problem faster. They help you transform the problem into an easier multiplication that gives the same answer.

For example:

48 × 5

may look like a multiplication-table problem, but you can rewrite it mentally as:

48 × 10 ÷ 2

480 ÷ 2 = 240

So:

48 × 5 = 240

That idea—changing a difficult calculation into a friendlier one—is the foundation of useful mental multiplication.

Educational mathematics resources from The Open University also recommend strategies such as doubling, halving, and transforming multiplication by 5, 9, 11, 20 and 50 into simpler operations.

This guide covers the multiplication shortcuts worth understanding, why they work, when to use them, and the mistakes that can make a “fast” method slower or less reliable.

Quick multiplication tricks

Multiplication	Mental shortcut
×5	×10, then halve
×9	×10, then subtract the number
×11	×10, then add the number
×15	×10 + half of ×10
×20	×2, then ×10
×25	×100, then divide by 4
×50	×100, then halve
×99	×100, then subtract the number
×101	×100, then add the number
×4	Double twice
×8	Double three times
Even-number products	Double one factor and halve the other

The shortcuts above are useful because they are based on ordinary multiplication properties rather than memorized magic.

1. Multiply by 5: multiply by 10 and halve

Multiplying by 5 becomes easier when you recognize:

5 = 10 ÷ 2

So:

number × 5 = number × 10 ÷ 2

Example: 46 × 5

Multiply by 10:

46 × 10 = 460

Halve:

460 ÷ 2 = 230

Therefore:

46 × 5 = 230

Example: 128 × 5

128 × 10 = 1,280

1,280 ÷ 2 = 640

Answer:

640

This is one of the most reusable multiplication tricks because multiplying by 10 and halving are usually easy mental operations.

2. Multiply by 9: multiply by 10 and subtract once

Nine is one less than ten:

9 = 10 − 1

Therefore:

number × 9 = number × 10 − number

Example: 47 × 9

First:

47 × 10 = 470

Then subtract 47:

470 − 47 = 423

So:

47 × 9 = 423

Example: 83 × 9

830 − 83 = 747

Answer:

747

This method is particularly useful when the original number is easy to subtract from its multiple of ten.

3. Multiply by 11: multiply by 10 and add once

Eleven is:

10 + 1

Therefore:

number × 11 = number × 10 + number

Example: 34 × 11

340 + 34 = 374

Example: 72 × 11

720 + 72 = 792

There is also a popular digit shortcut for two-digit numbers.

For:

32 × 11

Keep the outer digits and add them for the middle:

3 _ 2

3 + 2 = 5

So:

352

This shortcut works directly when the middle sum stays below 10.

What if the digits add to 10 or more?

Consider:

68 × 11

Add the digits:

6 + 8 = 14

You cannot simply write 6148.

Carry the 1:

6 + 1 = 7

Then write 4 and 8:

748

Check:

68 × 11 = 748

For many learners, the ×10 + original number method is easier to remember and less error-prone than memorizing separate carry rules.

4. Multiply by 15 using 10 and 5

Because:

15 = 10 + 5

you can calculate:

number × 15 = number × 10 + number × 5

And you already know that multiplying by 5 means multiplying by 10 and halving.

Example: 36 × 15

First find:

36 × 10 = 360

Then:

36 × 5 = 180

Add:

360 + 180 = 540

Answer:

540

Another way to think about it:

×15 = ×10 + half of ×10

This can be useful for prices, quantities and percentage-related calculations.

5. Multiply by 25: multiply by 100 and divide by 4

Because:

25 = 100 ÷ 4

you can use:

number × 25 = number × 100 ÷ 4

Example: 32 × 25

32 × 100 = 3,200

Then:

3,200 ÷ 4 = 800

So:

32 × 25 = 800

Faster variation

When the number is easily divisible by four, divide first:

32 ÷ 4 = 8

Then:

8 × 100 = 800

Another example:

76 × 25

76 ÷ 4 = 19

19 × 100 = 1,900

Answer:

1,900

This is usually much easier than multiplying 76 by 25 directly.

6. Multiply by 50: multiply by 100 and halve

Because:

50 = 100 ÷ 2

calculate:

number × 50 = number × 100 ÷ 2

Example: 38 × 50

38 × 100 = 3,800

Half:

1,900

So:

38 × 50 = 1,900

You can also halve first:

38 ÷ 2 = 19

Then:

19 × 100 = 1,900

The Open University includes multiplying by 5 and 50 through multiplication by powers of ten followed by halving among its recommended mental multiplication strategies.

7. Multiply by 4 or 8 using repeated doubling

Multiplication by powers of two can often be handled through doubling.

Multiply by 4

Double twice.

For:

37 × 4

First double:

37 × 2 = 74

Double again:

74 × 2 = 148

Answer:

148

Multiply by 8

Double three times.

For:

23 × 8

23 × 2 = 46

46 × 2 = 92

92 × 2 = 184

Answer:

184

This method is especially useful when you are comfortable doubling numbers mentally. Doubling and repeated doubling are also established mental multiplication strategies in mathematics teaching resources.

8. Double one factor and halve the other

Sometimes you can simplify a multiplication problem without changing the answer.

Consider:

16 × 35

Halve 16:

8

Double 35:

70

Now:

8 × 70 = 560

Therefore:

16 × 35 = 560

You can simplify again:

8 × 70

becomes:

4 × 140

Still:

560

Another example

25 × 24

Double 25:

50 × 12

Double again:

100 × 6

Answer:

600

Why does this work?

Because:

a × b = (a ÷ 2) × (2b)

when one factor can be halved conveniently.

This is not merely a shortcut. It is a flexible way of restructuring multiplication, and doubling-and-halving appears in formal mental-multiplication teaching material.

9. Break numbers apart using the distributive property

This may be the most useful multiplication strategy of all because it works with almost any numbers.

Suppose you need:

17 × 6

Break 17 into:

10 + 7

Then:

10 × 6 = 60

7 × 6 = 42

Add:

60 + 42 = 102

Therefore:

17 × 6 = 102

Another example: 23 × 14

Break 14 into:

10 + 4

Then:

23 × 10 = 230

23 × 4 = 92

Add:

230 + 92 = 322

Answer:

322

The underlying relationship is:

a × (b + c) = a × b + a × c

Unlike narrow numerical tricks, decomposition works across a huge range of multiplication problems.

If you are building mental calculation skills more broadly, Math Master’s Smart Tips & Tricks includes additional arithmetic techniques for multiplication, division, addition, subtraction and other topics.

10. Multiply by 99: multiply by 100 and subtract once

Since:

99 = 100 − 1

you can calculate:

number × 99 = number × 100 − number

Example: 47 × 99

First:

47 × 100 = 4,700

Subtract 47:

4,700 − 47 = 4,653

Answer:

4,653

Example: 82 × 99

8,200 − 82 = 8,118

Answer:

8,118

This is often easier than performing a traditional two-digit multiplication.

11. Multiply by 101: multiply by 100 and add once

The opposite idea works for 101:

101 = 100 + 1

So:

number × 101 = number × 100 + number

Example: 42 × 101

4,200 + 42 = 4,242

Answer:

4,242

Example: 73 × 101

7,300 + 73 = 7,373

Answer:

7,373

These ×99 and ×101 methods are examples of a larger strategy:

Use a nearby round number, then compensate.

12. Multiply numbers close to 100

One popular multiplication trick works particularly well when both numbers are close to 100.

Consider:

97 × 96

Both numbers are below 100.

Their deficits are:

100 − 97 = 3

100 − 96 = 4

Cross-subtract either deficit:

97 − 4 = 93

or:

96 − 3 = 93

Then multiply the deficits:

3 × 4 = 12

Combine:

93 | 12

Answer:

9,312

So:

97 × 96 = 9,312

Why does the trick work?

Write:

97 = 100 − 3

and:

96 = 100 − 4

Then:

(100 − 3)(100 − 4)

expands to:

10,000 − 700 + 12

which is:

9,312

This method is useful when both numbers are sufficiently close to 100, but it is much less useful for a calculation such as:

43 × 27

In that situation, decomposition is usually simpler.

Current exam-preparation resources commonly feature the near-100 method because it can reduce work for specific two-digit products.

Bonus trick: square numbers ending in 5

Suppose you need:

35 × 35

or:

35²

Take the number before the 5:

3

Multiply it by the next number:

3 × 4 = 12

Then append:

25

Answer:

1,225

So:

35² = 1,225

Another example: 65²

Take 6.

Multiply by the next integer:

6 × 7 = 42

Append 25:

4,225

Therefore:

65² = 4,225

Why does this work?

A number ending in 5 can be written as:

10n + 5

Squaring it gives:

(10n + 5)²

which simplifies to a number formed from:

n(n + 1) followed by 25.

This is a useful specialized shortcut, but remember that it works for squaring numbers ending in 5, not for arbitrary multiplication.

Which multiplication tricks are actually worth learning?

You do not need to memorize dozens of tricks.

Prioritize methods based on how widely you can reuse them.

Strategy	Usefulness	Best for
Decomposition	Very high	Almost any multiplication
Doubling and halving	Very high	Even factors
×10 then adjust	Very high	×9, ×11, ×99, ×101
×100 then divide	High	×25 and ×50
Repeated doubling	High	×4 and ×8
Numbers near 100	Medium	Two factors close to 100
Square ending in 5	Specialized	Numbers such as 25², 65²
Digit-specific tricks	Specialized	Particular number patterns

If you remember only three ideas, make them:

1. Break numbers apart.

2. Use nearby round numbers.

3. Double and halve when it simplifies the factors.

Those principles generate many of the “tricks” in this article automatically.

How to choose the fastest multiplication method

Before calculating, look at the numbers.

Is one number close to 10, 100 or 1,000?

Use compensation.

Example:

39 × 7

Think:

40 × 7 − 7

280 − 7 = 273

Is one factor 5, 25 or 50?

Use powers of ten followed by division.

Is one factor 4 or 8?

Try repeated doubling.

Is one factor even?

Consider doubling one side and halving the other.

Are both numbers close to 100?

Consider the near-100 method.

Are the numbers ordinary and not especially convenient?

Use decomposition.

The fastest mental calculator is not necessarily the person who calculates each step fastest.

It is often the person who recognizes the easier version of the problem first.

Worked examples: choosing the right trick

48 × 5

Best method:

×10 then halve

480 ÷ 2 = 240

68 × 25

Best method:

divide by 4, then ×100

68 ÷ 4 = 17

17 × 100 = 1,700

39 × 8

Possible method:

Repeated doubling:

39 → 78 → 156 → 312

Answer:

312

49 × 6

Best method:

Use 50:

50 × 6 − 6

300 − 6 = 294

18 × 35

Possible method:

Halve 18 and double 35:

9 × 70 = 630

24 × 17

Best general method:

Decompose 17:

24 × 10 = 240

24 × 7 = 168

240 + 168 = 408

Choosing a strategy is itself part of mental multiplication skill.

Multiplication tricks for competitive exams

Fast multiplication can be useful in aptitude, quantitative reasoning and other timed exams because routine arithmetic can consume time that could otherwise go toward solving the main problem.

Useful exam techniques include:

• fluent multiplication tables
• ×5, ×25 and ×50 shortcuts
• ×9 and ×11
• multiplication near 100
• percentage relationships
• doubling and halving
• squares of common numbers
• decomposition around 10, 50 and 100

However, a shortcut only saves time if you know it well.

Trying to remember an unfamiliar formula during an exam can be slower—and riskier—than ordinary multiplication.

Exam-focused competitors similarly emphasize practising shortcuts before relying on them under time pressure.

Do multiplication tricks replace multiplication tables?

No.

Multiplication tricks become much easier when your basic multiplication facts are already familiar.

For example:

17 × 8

can be decomposed into:

10 × 8 + 7 × 8

But you still benefit from knowing:

7 × 8 = 56

Then:

80 + 56 = 136

Basic fact recall and flexible strategies work together.

You do not need to choose between “memorization” and “thinking.” Knowing common multiplication facts gives you building blocks; strategies help you combine those blocks efficiently.

Common mistakes with fast multiplication tricks

Using the wrong trick

Do not use the near-100 method on numbers that are nowhere near 100 just because you learned it recently.

Better approach: choose the strategy based on the numbers.

Forgetting the adjustment

For:

49 × 7

you might calculate:

50 × 7 = 350

but forget to subtract 7.

Correct answer:

343

Mishandling carries when multiplying by 11

The simple “add the two digits” version needs extra care when their sum reaches 10 or more.

Use:

×10 + original number

if that feels safer.

Chasing speed before accuracy

A shortcut that produces more errors is not useful.

Learn it slowly before timing yourself.

Memorizing without understanding

If you know why a method works, you are more likely to remember when it applies and notice when it does not.

How to practise multiplication for faster calculation

Start with one technique at a time.

Step 1: Understand the method

For example, understand why:

×9 = ×10 − original number

Step 2: Solve five easy examples

Try:

12 × 9

24 × 9

37 × 9

52 × 9

81 × 9

Step 3: Check every answer

Accuracy comes before speed.

Step 4: Mix the method with others

Once ×9 feels natural, mix it with ×5, ×11 and ordinary multiplication.

Now you must decide which method to use rather than being told.

Step 5: Add short timed practice

Only start focusing heavily on speed after the method is reliable.

You can practise multiplication and other arithmetic skills using Math Master and explore additional methods through Smart Tips & Tricks.

For mobile practice:

Download Math Master on Google Play

Download Math Master on the App Store

If competition helps keep your practice consistent, you can also track activity through the Math Master leaderboard.

10 multiplication questions to practise

Try these mentally before looking at the answers.

1. 48 × 5

Answer:

240

2. 37 × 9

370 − 37 = 333

3. 43 × 11

430 + 43 = 473

4. 28 × 25

28 ÷ 4 × 100

7 × 100 = 700

5. 36 × 50

36 ÷ 2 × 100

18 × 100 = 1,800

6. 24 × 8

Double three times:

48 → 96 → 192

7. 18 × 45

Double 45 and halve 18:

9 × 90 = 810

8. 46 × 99

4,600 − 46 = 4,554

9. 97 × 98

Deficits:

3 and 2

Cross-subtract:

95

Multiply deficits:

6

Because the base is 100, write the final part as two digits:

06

Answer:

9,506

10. 75²

Take 7.

7 × 8 = 56

Append 25:

5,625

A 10-minute multiplication practice routine

A simple routine could look like this:

Minutes 1–2: multiplication-table recall

Minutes 3–4: ×5, ×9 and ×11

Minutes 5–6: ×25, ×50 and doubling

Minutes 7–8: decomposition and compensation

Minute 9: mixed problems

Minute 10: review mistakes

Do not treat ten minutes as a magic duration. It is simply a manageable routine that can make consistent practice easier.

The key is to practise often enough that you begin recognizing patterns without having to consciously recall a rule every time.

FAQ

What is the fastest multiplication trick?

There is no single fastest method for every multiplication problem. The best method depends on the numbers. Decomposition, doubling and halving, and using nearby round numbers are among the most reusable approaches.

What is the trick for multiplying by 5?

Multiply the number by 10, then divide by 2. For example, 64 × 5 becomes 640 ÷ 2 = 320.

How do you multiply by 9 quickly?

Multiply by 10 and subtract the original number. For example, 36 × 9 = 360 − 36 = 324.

What is the multiplication trick for 11?

For any number, multiply by 10 and add the original number. For example, 47 × 11 = 470 + 47 = 517. A digit-based shortcut also exists for two-digit numbers, but you must handle carrying when the two digits add to 10 or more.

How do you multiply by 25 mentally?

Divide the other number by 4 and multiply by 100 when division by four is convenient. For example, 64 × 25 = 16 × 100 = 1,600.

How do you multiply numbers close to 100?

Find each number’s difference from 100, cross-subtract one difference, multiply the differences, and combine the parts using base 100. This works particularly well when both factors are close to 100.

What multiplication tricks are best for exams?

Useful exam techniques include decomposition, ×5, ×9, ×11, ×25, ×50, doubling and halving, multiplication around 100 and fluent multiplication-table recall. Use only methods you have practised enough to apply reliably.

Do multiplication tricks improve calculation speed?

They can reduce the number or difficulty of calculation steps when the method fits the problem. Their usefulness depends on recognizing the correct strategy and applying it accurately.

Should I memorize multiplication tables or learn tricks?

Both are useful. Multiplication-table fluency provides basic facts, while mental multiplication strategies help combine and transform those facts for larger problems.

How can I get faster at multiplication?

Build reliable basic facts first, then practise reusable strategies such as decomposition, compensation and doubling. Once accuracy is consistent, add mixed and timed practice.

Conclusion

Fast multiplication is not mainly about memorizing dozens of impressive shortcuts.

It is about recognizing structure.

When you see ×5, think ×10 and halve.

When you see ×9, think ×10 minus one group.

When you see ×25, think ×100 divided by four.

When one factor is even, consider doubling and halving.

When the numbers are awkward, break them apart.

When they are close to a round number, use that round number and compensate.

These principles are more valuable than isolated tricks because you can reuse them across thousands of calculations.

To practise multiplication regularly, use Math Master, explore more math tips and tricks, or practise on your phone through Google Play and the Apple App Store.

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Math Master editorial team

The Math Master editorial team creates practical educational resources that help learners strengthen arithmetic, mental calculation, number sense and mathematical problem-solving. Math Master provides interactive questions, quizzes, puzzles, games and skill-based mathematics practice for learners who want to build stronger calculation habits.