Aptitude - Numbers - Discussion

Discussion :: Numbers - General Questions (Q.No.15)

15. 

72519 x 9999 = ?

[A]. 725117481
[B]. 674217481
[C]. 685126481
[D]. 696217481
[E]. None of these

Answer: Option A

Explanation:

72519 x 9999 = 72519 x (10000 - 1)
= 72519 x 10000 - 72519 x 1
= 725190000 - 72519
= 725117481.

Priya P. said: (Nov 30, 2010)  
Great!

Nandish said: (Mar 8, 2011)  
What if 72519*9998 = ... is it 725044962...

Thimoty said: (Jul 22, 2011)  
This is a simplest shortcut method for ever.

Poornima Hassan said: (Aug 31, 2011)  
725190000
- 72519
............
725117481


this is the easiest method dear

Akshay said: (Feb 19, 2016)  
So easy method.

Sree said: (Jul 20, 2016)  
It is very simple method 72519 * 9999.

72519 * 9000 = 652671000,
72519 * 900 = 65267100,
72519 * 90 = 6526710,
72519 * 9 = 652671.

Then 652671000 + 65267100 + 6526710 + 652671 = 725117481.

Krishnamurthy said: (Aug 19, 2016)  
The easiest method can be:

72519 x 9999.

If the multiplier is series of 9 (i. e. 9, 99, 999. ) then,

Add every digit in the given answer (i.e. 7 + 2 + 5 + 1 + 1 + 7 + 4 + 8 + 1 = 36, add the answer again, i.e. 3 + 6 = 9).

And if the final answer is 9 then that number itself answers.

Roshan said: (Jan 16, 2017)  
I think it's 72446481.

Is it correct?

Vamsi Aripaka said: (May 17, 2018)  
Thank for explaining the solution.

Smit said: (Jun 5, 2018)  
If we multiply all then option C is correct.

Mustafa said: (Jun 27, 2019)  
It works if m * n when the numbers in m > n and n = any number of 9's sequence.

1) count number of 9's in n.
2) add those many 0's in the m number.
3) subtract the original number.

eg> 72519 * 9999.
m=5 , n = 4 thus m>n.
721590000-72519= 725117481.

Mustafa said: (Jun 27, 2019)  
This trick always works if m * n when the numbers in m > n and n = any number of 9's sequence.

1) Count number of 9's in n.
2) Add those many 0's in the m number.
3) Subtract the original number.

eg> 72519 * 9999.
m=5 , n = 4 thus m>n.
721590000-72519= 725117481.

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