Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 15)
15.
72519 x 9999 = ?
Answer: Option
Explanation:
| 72519 x 9999 | = 72519 x (10000 - 1) |
| = 72519 x 10000 - 72519 x 1 | |
| = 725190000 - 72519 | |
| = 725117481. |
Discussion:
16 comments Page 1 of 2.
Aashu said:
5 years ago
7 + 2 + 5 + 1 + 9 = 24 again 2 + 4=6
9 + 9 + 9 + 9 = 36 again 3 + 6 =9
Given =72519 * 9999 = 9 * 6 = 54 sum of 5 + 4= 9
Now find the sum of the digits in the given option
A)7 + 2 + 5 + 1 + 1 + 7 + 4 + 8 + 1 = 9,
Similarly for
B)4
C)5
D)8
So, option A is the correct answer. Hope my answer is useful.
9 + 9 + 9 + 9 = 36 again 3 + 6 =9
Given =72519 * 9999 = 9 * 6 = 54 sum of 5 + 4= 9
Now find the sum of the digits in the given option
A)7 + 2 + 5 + 1 + 1 + 7 + 4 + 8 + 1 = 9,
Similarly for
B)4
C)5
D)8
So, option A is the correct answer. Hope my answer is useful.
(17)
Krishnamurthy said:
9 years ago
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.
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.
Mustafa said:
7 years ago
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.
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.
(1)
Mustafa said:
7 years ago
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.
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.
(1)
Anurag said:
3 years ago
@All.
The best short trick to multiply any digit with 99,999,999,99999999,..
Example;
33 * 99 = 33 -1 || 9-3 || 10-3 => 3267.
237 * 999 = 237-1 || 9-2 || 9-3 || 10 - 7 (10 - last digit) => 236763.
The best short trick to multiply any digit with 99,999,999,99999999,..
Example;
33 * 99 = 33 -1 || 9-3 || 10-3 => 3267.
237 * 999 = 237-1 || 9-2 || 9-3 || 10 - 7 (10 - last digit) => 236763.
(2)
Sree said:
9 years ago
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.
72519 * 9000 = 652671000,
72519 * 900 = 65267100,
72519 * 90 = 6526710,
72519 * 9 = 652671.
Then 652671000 + 65267100 + 6526710 + 652671 = 725117481.
(1)
Abid said:
5 days ago
It is much easier if we find the sum of the digits. Only opt A's Digits' sum is divisible by 9.
So, that's the answer.
So, that's the answer.
Poornima hassan said:
1 decade ago
725190000
- 72519
............
725117481
this is the easiest method dear
- 72519
............
725117481
this is the easiest method dear
Thimoty said:
1 decade ago
This is a simplest shortcut method for ever.
Smit said:
8 years ago
If we multiply all then option C is correct.
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