Whether or not you are a fan of mathematics, you will appreciate a faster way of solving math problems, without having to struggle through complex solutions or looking for extra math help or a calculator every time. Knowing some math tricks could definitely help.

You can solve many arithmetic problems without a calculator almost instantly and in this blog post we are going to show you how.

**Math trick 1: Instant multiplication of 11 by any two-digit number**

Let’s say you need to multiply 11 by some 2-digit number instantly. It is very easy, if you know the secret.

Consider the following problem:

**43 x 11**

To solve this problem instantly, just add the digits of 43 and put the result in between these digits:

**43 x 11: ****4 + 3 = 7, the answer is 4**73

Check the answer by using the calculator to confirm that it works 🙂

Here are some more examples:

**18 x 11: ****1 + 8 = **9, the answer is 198

**10 x 11: ****1 + 0 = **1, the answer is 11

**13 x 11: ****1 + 3 = **4, the answer is 143

Well, this was only the first part of the trick.

What would the answer be for** 78 **x 11?

The trick would follow the same pattern, but we now have to carry 1-tens to the head digit.

The result is** 7+8=15**, so we need to put the right digit in between the digits** 7** and** 8** as we did in the above section and add 1-tens to the left:

**78 x 11: ****7 + 8 = **15, the answer is (7+1)58 => 858

Here are some more examples:

**99 x 11: ****9 + 9 = **18, the answer is (9+1)89 => 1089

**66 x 11: ****6 + 6 = **12, the answer is (6+1)26 => 726

**55 x 11: ****5 + 5 = **10, the answer is (5+1)5 => 75

**Math trick 2: Instant squaring of two-digit numbers ending in 5**

As you may already know, the square of a number is that number multiplied by itself.

The algorithm is: Multiply the first digit by the digit 1 more than the given one and put 25 (the square of 5) following the result of the first computation.

Consider the following problems:

**25 x 25: 2 x 3 = 6, the answer is 625 **

**75 x 75: 7 x 8 = 56, the answer is 5625**

**45 x 45: 4 x 5 = 20, the answer is 2025**

**95 x 95: 9 x 10 = 90, the answer is 9025**

**15 x 15: 1 x 2 = 2, the answer is 225**

**55 x 55: 5 x 6 = 30, the answer is 3025**

**85 x 85: 8 x 9 = 72, the answer is 7225 **

**Math trick 3: Left-to-Right addition of numbers**

The assumption here is that you are able to add and subtract Natural numbers.

We will start with adding two-digit numbers and then will continue with adding three or more digit numbers.

The easiest two-digit addition problems are those that do not require you to carry any numbers.

For example:** 87 + 12**

To solve this, first add** 10 a**nd** 87 a**nd then add** 2 t**o the result:

The calculations are as follows:** (87 + 10) + 2 = 97 + 2= 99**

Here are more examples:

**13 + 15 = (13 + 10) +5 = 23 + 5 = 27**

**18 + 11 = (18 + 10) + 1 = 28 + 1 = 29 **

Even though this looks very simple, it shows the fundamental method of mental process.

Now let’s try to add the numbers that require us to carry the number:

**15 + 17 = (15 + 10) + 7 = 25 + 7 = 32**

**26 + 26 = (26 + 20) + 6 = 56 + 6 = 62**

**38 + 67 = (38 + 60) + 7 = 98 + 7 = 105 **

Try practicing this method and you will be able to add the numbers very fast.

The addition of three-digit numbers looks the same.

Now it is your turn to try:

**537 + 467 = (537 + 400) + 60 + 7 = ?**

**203 + 145 = (203 + 100) + 40 + 5 = ?**

Those were a bit more difficult, but if you first practice the addition of two-digit numbers, you will be able to add three-digit numbers instantly as well.

**Math trick 4: Left-to-Right subtraction of numbers **

When doing subtraction of any two-digit numbers, you need to simplify the problem such that you are left with subtracting or adding a one-digit number.

Let’s consider the example: ** 96 – 35 **

To solve this, first subtract** 30 **and then subtract** 5 **from the result:

**96 – 35 = (96 – 30) – 5 = 66 – 5 = 61 **

Here are some more examples:

**67 – 23 = (67 – 20) – 3 = 47 – 3 = 44**

**38 – 13 = (38 – 10) – 3 = 28 – 3 = 25**

**99 – 98 = (99 – 90) – 8 = 9 – 8 = 1**

Subtracting looks easy when there is no borrowing (when a larger digit on the right is being subtracted from a smaller one).

The good thing is that subtraction problems can be turned into addition.

Let’s consider an example:

**77 – 18 **

For this example, the best strategy would be to subtract** 20 f**rom** 77, t**hen add** 2.**

**77 – 18 = 77 – (20 – 2) = (77 – 20) + 2 = 57 + 2 = 59 **

So, the rule here is: round the second number up to a multiple of ten, then subtract the rounded number and then add back the difference.

Here are some more examples:

**64 – 29 = 64 – (30 – 1) = (64 – 30) + 1 = 34 + 1 = 35**

**91 – 27 = 91 – (30 – 3) = (91 – 30) + 3 = 61 + 3 = 64 **

There are lots of other math tricks that can be used to solve problems in a more elegant way. Are there any other ones that you know? Comment below 🙂

## There is no comments yet