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14 Sept 2026 · 11 min read
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Mental calculation is often treated as something children either “have” or do not have. In reality, a large part of fast calculation comes from recognising patterns. When a child sees 9 × 48 as “10 × 48 minus 48,” or recognises that 75² can be solved without conventional multiplication, the calculation becomes shorter because the child has identified a useful structure.
That is one of the reasons Vedic Mathematics is popular as a mental-maths approach. Several of its commonly taught techniques are built around decomposing numbers, using complements, working with powers of 10, and recognising special patterns. The important point is that these methods are shortcuts for particular number structures, not replacements for understanding ordinary arithmetic. A child should know why a method works and when it is appropriate before trying to perform it mentally.
The five tricks below correspond to the five techniques highlighted in the accompanying visual: 9's Trick, Base 10, Multiplication Trick, Squaring Trick and Complementary Numbers. Some of these ideas overlap mathematically, particularly base-10 and complementary-number methods, but each gives children a different mental route into a calculation.
Multiplying by 9 can look like an ordinary multiplication problem, but there is a much easier relationship hiding inside the number. Since 9 is one less than 10, multiplying a number by 9 is the same as multiplying it by 10 and then subtracting the original number.
For example, instead of calculating 47 × 9 through conventional multiplication, think:
47 × 10 = 470
470 − 47 = 423
So, 47 × 9 = 423.
The same idea works with larger numbers. For 126 × 9, calculate 126 × 10 = 1,260 and subtract 126, giving 1,134. The mental calculation is particularly useful because multiplying by 10 is immediate in our decimal system.
This method can also be extended to numbers such as 99 and 999. Since 99 is 100 − 1, 64 × 99 can be thought of as 64 × 100 − 64, giving 6,336. Similarly, 38 × 999 can be calculated as 38 × 1,000 − 38 = 37,962. The broader skill here is not memorising a “9 trick” in isolation; it is learning to notice when a number sits just below a convenient power of 10.
A child can practise this pattern with examples such as 26 × 9, 53 × 9, 72 × 9 and 84 × 99. Once the relationship becomes familiar, the child can begin recognising similar opportunities with 999 and other numbers close to powers of 10.
The decimal number system gives us a powerful mental-calculation advantage because numbers such as 10, 100 and 1,000 are easy to work with. Vedic Mathematics frequently uses these numbers as bases when a calculation involves numbers close to them.
Suppose a child needs to calculate 98 × 97. Instead of treating it as a conventional two-digit multiplication, notice that both numbers are close to 100:
The deviations are small, so the calculation can be reorganised around the base 100. Cross-subtracting gives:
98 − 3 = 95
Then multiply the deviations:
2 × 3 = 6
Because the base is 100, the second part occupies two places, so the result is:
95 | 06 = 9,506
Thus, 98 × 97 = 9,506.
This is the principle behind the Nikhilam approach, commonly translated as “all from 9 and the last from 10.” It is particularly useful when numbers lie close to 10, 100 or 1,000.
The important thing for children is to understand why the method becomes easier near a base. The calculation is taking advantage of the small differences between the numbers and a convenient power of 10 rather than performing every digit-by-digit multiplication separately.
It is most useful when both numbers are reasonably close to the same base. For example, 996 × 998 is a much better candidate for a base-1,000 method than a calculation such as 437 × 682. Mental maths becomes faster when children learn to choose the method based on the structure of the numbers instead of trying to apply one trick to everything.
Another well-known Vedic Mathematics approach is Urdhva-Tiryagbhyam, often translated as “vertically and crosswise.” Unlike the near-base method, this approach can be used for general multiplication and shows children another way to organise the partial products.
Consider 23 × 14.
Start with the units:
3 × 4 = 12
Then move crosswise:
2 × 4 + 3 × 1 = 8 + 3 = 11
Finally, multiply the tens:
2 × 1 = 2
After handling the carries appropriately, the answer is 322.
The value of this technique is not simply that it produces an answer quickly. It encourages children to see multiplication as a structured combination of place values rather than as a long sequence of disconnected steps. The same vertically-and-crosswise idea can be extended to larger numbers, although the amount of mental work naturally increases as the numbers become more complicated.
For children learning mental maths, it is worth introducing this only after place value and ordinary multiplication are secure. A shortcut becomes useful when it reduces cognitive load; it becomes confusing when the child is still unsure about what the individual products represent.
Start with simple two-digit examples such as 21 × 13 and 32 × 12, then gradually introduce numbers where the cross-products require more mental calculation. Children should first explain each step aloud or on paper before trying to perform the whole process mentally.
One of the most satisfying Vedic Mathematics patterns is the shortcut for squaring numbers that end in 5. It is associated with the sutra Ekadhikena Purvena, commonly translated as “by one more than the previous one.” The method works because of the algebraic structure of a number ending in 5.
Take 35².
Ignore the final 5 for a moment. The number before it is 3.
Add 1:
3 + 1 = 4
Multiply:
3 × 4 = 12
Now place 25 after the result:
1,225
Therefore:
35² = 1,225
The same pattern works for larger numbers:
85²
8 × 9 = 72
Attach 25 → 7,225
Or:
125²
12 × 13 = 156
Attach 25 → 15,625
The reason this works is not magic. If a number ending in 5 is written as 10n + 5, squaring it gives:
(10n + 5)² = 100n(n + 1) + 25
So the multiplication of the number before 5 by the number one greater produces the part before the final 25.
This is an excellent example of how mental mathematics can become easier when children recognise algebraic patterns without necessarily having to write down the full algebra every time.
The idea of a complement is central to several fast-calculation techniques. A complement simply tells us how much a number needs to reach a convenient base.
For example:
Once children become comfortable finding these differences mentally, they can use them in multiplication and other calculations.
Consider 97 × 96.
Using 100 as the base:
97 is 3 below 100.
96 is 4 below 100.
Now cross-subtract:
97 − 4 = 93
Then multiply the complements:
3 × 4 = 12
Combine the two parts:
93 | 12 = 9,312
So:
97 × 96 = 9,312.
This is another application of the near-base Nikhilam method, where the deviations from the base are used instead of performing the full multiplication.
The complementary-number idea is useful beyond this particular multiplication technique. It trains children to ask a valuable mental-maths question: “How far is this number from something easier to work with?” That question can turn an apparently difficult calculation into a much simpler one.
The biggest advantage of these methods is not that children memorise five clever formulas. It is that they begin to look at numbers differently.
Traditional calculation often teaches children a reliable sequence of operations. Mental mathematics adds another layer: deciding whether the numbers contain a pattern that can make the calculation shorter. A child who notices that 99 is one below 100, that 75 ends in 5, or that 48 × 9 can be treated as 48 × 10 − 48 is making a mathematical decision before calculating.
That kind of flexibility is valuable because not every trick works for every problem. A child should not try to force a base-100 method onto numbers that are nowhere near 100, just as the squaring-by-25 pattern should not be used for a number that does not end in 5.
The best way to introduce mental-maths shortcuts is to make the pattern visible before asking children to calculate quickly. Start with a small number of examples and ask the child what they notice. For the 9's trick, they might discover that multiplying by 9 is the same as multiplying by 10 and removing one original group. For complementary numbers, they can practise finding how far numbers are from 10 or 100 before using those complements in multiplication.
Once the child understands the structure, short mental challenges can make practice more engaging. Give them a calculation, allow a few seconds to identify the most efficient method, and then ask them to explain the route they chose. This makes the activity about mathematical reasoning as well as speed.
It is also useful to mix ordinary calculations with trick-friendly calculations. If every question is deliberately chosen to fit a particular trick, children may learn to recognise the exercise rather than the mathematics. Mixing the problems forces them to decide whether a shortcut is actually useful.
Try these without writing down the conventional multiplication method:
36 × 9
98 × 97
24 × 13
75²
96 × 94
The interesting part is not simply getting the five answers. Ask the child which trick they noticed first and why they chose it. That explanation reveals whether they are beginning to recognise number relationships or merely memorising procedures.
Vedic Mathematics can make mental calculation feel surprisingly quick, but its deeper value lies in developing number sense, pattern recognition and flexibility. The five techniques highlighted here—9's Trick, Base 10, Multiplication Trick, Squaring Trick and Complementary Numbers—give children different ways to reorganise familiar calculations. With practice, the aim is not to calculate everything through a shortcut; it is to become better at seeing when a shortcut exists.
Children should first understand the mathematical relationship behind a Vedic Maths technique rather than memorising a sequence of steps. The article’s five methods work by recognising patterns such as numbers close to powers of 10, numbers ending in 5, and multiplication relationships. Once the child understands when a method is useful, they can practise applying it mentally.
They can be useful when they help children recognise patterns and choose a more efficient calculation method. For example, multiplying by 9 can be reframed using 10, while numbers close to 100 can be handled through complements. The aim should not be to make every calculation faster through a shortcut, but to help children recognise when a particular shortcut makes sense.
The article does not suggest one fixed starting age because readiness depends on a child's understanding of basic arithmetic and place value. Children should be comfortable with the underlying mathematical concepts before introducing more advanced shortcuts. For younger learners, simple number relationships can provide a foundation before they move towards techniques involving multiplication, squares and powers of 10.
No. Memorising a procedure without understanding when to use it can actually make mental maths less flexible. Children should learn to examine the numbers, identify useful relationships and decide whether a particular method will simplify the calculation. This is why the article emphasises that these techniques are not shortcuts to memorise blindly.
No. Vedic Maths techniques are best treated as additional strategies rather than replacements for fundamental mathematical understanding. Conventional methods help children understand place value, operations and mathematical procedures, while mental-maths techniques can give them alternative ways to approach suitable calculations. A strong learner should be able to choose between methods depending on the numbers and the problem.