# 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

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.