Thursday, 13 April 2017

Calculation Tricks V- How to Easily Multiply Two Numbers

Learn this calculation trick and save time every time you multiply two numbers.

Multiply Two Numbers
Questions in the Quantitative Aptitude section of all competitive exams like SBI PO, IBPS, SSC CGL need you not only to be conceptually strong but also know calculation tricks that help you save time. If you are one of those who skips a question just because it needs you to multiply then this calculation trick is especially for you!
So here is the 15th calculation trick in the series of blog posts with smart methods that will help you solve questions in 5- 10 seconds that would otherwise take 30- 45 seconds.
multiply two numbers

 

Multiplication

Ok! now before you rush to kill us for explaining something that you learnt in 3rd grade in school let me tell you why we are doing it!  Surely no question in a competitive exam will directly ask you to multiply two numbers but almost every second question will require you to multiply two numbers to reach the answer.


Multiply Two Numbers- Example

73 x 87 = ?
1) 6421      2) 6351      3) 6251      4) 4921      5) None of these


Conventional Method to Multiply Two Numbers

Agreed that you are an expert in this mathematical operation, you can probably multiply numbers even in sleep but can you say the same for all numbers? The instant the read the question above you quickly start scribbling and multiplying the numbers to reach the answer which takes about 15 seconds. 
multiply two numbers

Definitely the correct answer but not a good method when there is a super quick calculation trick for this!

Smart method to Multiply Two Numbers

Let’s save you some precious 10 seconds by discussing a smart method that will have to smiling from ear to ear. We will simply use the algebraic identity (a+ b) (a- b) to reach the answer.
We know (a+ b) (a-b) = a2 – b2

Step 1:
(80 – 7) (80 + 7) = 802 – 72 = 1600- 49 = 6351

A calculation as complex as this takes only 5 seconds and we get our answer!
multiply two numbers
Watch the video below to see our expert faculty explain the super quick calculation method to multiply two numbers.


Multiply the two numbers using calculation tricks-
Question 1:   44 x 56 = ?
1) 2724      2) 2684      3) 2464      4) 1024      5) None of these

Question 2:   82 x 98 = ?
1) 8036      2) 7456      3) 4686      4) 6646      5) None of these

Do write your answers in the comments below and tell us how many seconds it took you to multiply the two numbers.

Stay tuned to this space for more smart methods and don’t forget to use these smart methods when you practice!
multiply two numbers


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