How fast can you multiply the following numbers:* *11 * 19 = ?27 * 23 = ?39 * 31 = ?42 * 48 = ?53 * 57 = ?64 * 66 = ? 107 * 103 = ?112 * 128 = ?124 * 126 = ? Well it should not take more than *2-3 seconds 
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How fast can you multiply the following numbers:
11 * 19 = ?
27 * 23 = ?
39 * 31 = ?
42 * 48 = ?
53 * 57 = ?
64 * 66 = ?
107 * 103 = ?
112 * 128 = ?
124 * 126 = ?
Well it should not take more than 2-3 seconds😲 for those who know the trick, for those who don't know, even if they apply the direct multiplication method, it will take more than that in most of the cases.
According to this trick, the first part of the numbers should be the same
example,
in 11 * 19, 27 * 23, 112 * 118, 124 * 126 the first part of the numbers are same,
now the second condition is that the second part of the numbers should have the sum exactly 10
as in
11 * 19, 27 * 23, 112 * 118, 124 * 126
Only when both conditions are fulfilled, then the method works.
Only when both conditions are fulfilled, then the method works.
Alright, now according to the method multiply the first part of the number with 1 more than the number, i.e. if first part is 11, then multiply with 12, if its 1 then with 2, and so on.
11 * 19 = 2_ , 112 * 118 = 132_
Next, multiply second part of both the numbers together to get second part of the answer, if it comes a single digit then put a zero in front else no need for zero, like in
11 * 19 = 209 , 112 * 118 = 13216
Just understanding the method takes little time, and with little practice you will be applying it with lightning speed👏 , just look at the following numbers and i am sure within 2 seconds, you can figure out the answer
11 * 19 = 209
27 * 23 = 621
39 * 31 = 1209
42 * 48 = 2016
53 * 57 = 3021
64 * 66 = 4224
107 * 103 = 11021
112 * 128 = 15616
124 * 126 = 15624
it's easy to learn a few shortcuts a day and practice each for 5-10 minutes, rather than cramming most of them and forgetting the next day, try to apply shortcuts when you solve problems at home, so that you can apply them in exams easily, i am practicing shortcuts and will post them frequently, if anyone wants to share special tricks, then please do, u r most welcome. these shortcuts may make the difference in SSC and CAT this year for you, so do not ignore them.
OK friends, so here's the next trick
Well this is very simple and most of us are in fact familiar with it, but if you are not then you will be in a few seconds.
The trick is to find squares of numbers ending in 5. For that just remember 5^2 = 25 (simple)
Now let's take any number ending in 5, say N5, its square will be have last part always as 25, and first part will be (N * N+1).
example, 25^2 has last part as 25, now first part = 2*3=6, hence 25^2 = (2*3) 25 = 625
similarly, 35^2 = (3*4) 25 = 1225
45^2 = (4*5) 25 = 2025
125^2 = (12*13) 25 = 15625
and so on 😃
Square of Numbers near 100:
Let me explain this rule by taking examples
96^2 :-
First calculate 100-96,
it is 4so 96^2 = (96-4)----4^2 = 9216
similarly106^2 :-
First calculate 106-100,
it is 6so 106^2 = (106+6)----6^2 = 11236
Example. An other case arises
110^2 = (110+10)----100
= (120+1)----00
= 12100
similarly
89^2 = (89-11)----121
= (78+1)----21
= 7921
Square of any two digit number: Easiest method 😁
Let me explain this trick by taking examples
67^2 = [6^2][7^2]+20*6*7
= 3649+840
= 4489
similarly
25^2 = [2^2][5^2]+20*2*5
= 425+200
= 625
Take one more example
97^2 = [9^2][7^2]+20*9*7
= 8149+1260
= 9409
Here [] is not an operation, it is only a separation between initial 2 and last 2 digits
Example.
Here an extra case arises Consider the following examples for that
91^2 = [9^2][1^2]+20*9*1
= 8101+180
= 8281
👍👍👍👍😉
Statutory Warning: Calculators are for Brainless people 😛 
Alright guys.. New trick:Calculate 456456*999999?? Answer can be done in 5 seconds...!!
U read it right ...That's 5 seconds
well the answer is 456455543544...!!!
it took 3 secs for me...now the trick itself :
456456*999999 = 456455543544
step-1: 456456-1= 456455(first half answer)--->A
999999-A= 543544--->B
the Answer is AB= 456455_543544
More Examples:
345*999= 344655 (calculate in mind)
999*999= 998001 (again calculate in mind)
123456789*999999999= 123456788876543211
Amazing Trick right...!!!
Note: number of digits in the no. and 9999...9 should be same.
Statutory Warning: Calculators are for Brainless people Alright guys.. New trick:Calculate 456456*999999?? Answer can be done in 5 seconds...!!
U read it right ...That's 5 seconds
well the answer is 456455543544...!!! it took 3 secs for me...now the trick itself :456456*999999 = 456455543544step-1: 456456-1= 456455(first half answer)--->A999999-A= 543544--->Bthe Answer is AB= 456455_543544More Examples:
345*999= 344655 (calculate in mind)
999*999= 998001 (again calculate in mind)
123456789*999999999= 123456788876543211Amazing Trick right...!!!
Note: number of digits in the no. and 9999...9 should be same.
The sum of thirty-two consecutive natural numbers is a perfect square. What is the least possible sum of the smallest and the largest of the thirty-two numbers?
Here is some of the tricks i learned while preparing.Hope it will help.
Strange Facts about Numbers #4 Any even number above 3 can be expressed as sum of two prime numbers. 4 = 2 + 2, 6 = 3 + 3, 8 = 3 + 5, 10 = 5 + 5, 12 = 5 + 7, and so on. It's not proven yet and so is entitled to be a conjecture. Can anyone name this?
Strange Facts about Numbers #5 145 has a unique property, the sum of the factorials of it's digits gives you the number itself. So, 1! + 4! + 5! = 145. Can be useful for XAT alphanumeric questions.#XAT There are a lot of numbers that possess similar property. Can you find any one of them? #Numberrs
For speed maths video tutorial , i think this playlist is really help , it has videos on quick addition , subtraction and multiplication . Best speed maths tricks for fast calculation | Vedic maths | Quick solving: https://www.youtube.com/playlist?list=PLnNa3uNHAm1JBdoM5cmcXeU2qs6lbV_92
A good source/book for clearing concepts and practice for Quant chapters like Permutation and Combination, Probability, Mensuration ??