Mathematics · Quantitative Aptitude

Number Operations and Properties

974 Questions

Improve your quantitative aptitude with these number operations and properties questions. The topics range from basic subtraction and division to highest common factor and roman numerals. Regular practice of these fundamentals builds speed for exams.

Basic arithmetic operationsHCF and number propertiesRoman numeral calculationsNumber series evaluation

Number Operations and Properties Questions

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round-off $4353$ to nearest $100$.

  1. $4353$
  2. $4350$
  3. $4360$
  4. $4400$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\Rightarrow$  The given number is $4353$

$\Rightarrow$  In number 4353, its tens digit is 5, which is equal to 5. 
$\Rightarrow$  So, we increase the digits at hundreds place by 1 and replace each one of the digits at tens and ones place by 0 to round off the given number to nearest to 100.

$\therefore$   The number becomes $4400$

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round-off $52,398$ to nearest $1000$.

  1. $52,390$
  2. $52,400$
  3. $52,000$
  4. $53,000$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\Rightarrow$  The given number is $52,398$

$\Rightarrow$  In number $52398$, its hundred digit is $3$, which is less than $5$. 
$\Rightarrow$  So, we replace each one of the digits at hundreds, tens and ones place by $0$ to round off the given number to nearest to $1000$.

$\therefore$   The number becomes $52,000$

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round-off $3789$ to nearest $100$

  1. $3789$
  2. $3790$
  3. $3800$
  4. $4000$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\Rightarrow$  The given number is $3789$

$\Rightarrow$  In number 3789, its tens digit is 8, which is greater than 5. 
$\Rightarrow$  So, we increase the digits at hundreds place by 1 and replace each one of the digits at tens and ones place by 0 to round off the given number to nearest to 100.

$\therefore$   The number becomes $3800$

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round-off $47,897$ to nearest $1000$.

  1. $47,897$
  2. $48,000$
  3. $47,900$
  4. $47,890$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\Rightarrow$  The given number is $47,897$

$\Rightarrow$  In number 47897, its hundred digit is 8, which is greater than 5. 
$\Rightarrow$  So, we increase the digits at thousand place by 1 and replace each one of the digits at hundreds, tens and ones place by $0$ to round off the given number to nearest to 1000.

$\therefore$   The number becomes $48,000$

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Mark the correct alternative of the following.
Total number of numbers which when rounded off to nearest ten give us $200$ is?

  1. $9$
  2. $10$
  3. $8$
  4. $7$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$195, 196, 197, 198, 199, 200, 201, 202, 203, 204$ are the numbers that when rounded off to nearest ten give us $200$.


Hence, total number of numbers which when rounded off to nearest ten give us $200$ is $10$.

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Mark the correct alternative of the following.
The smallest number which when rounded off to the nearest hundred as $600$, is?

  1. $550$
  2. $595$
  3. $604$
  4. $599$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The number from $550$ to $649$ are rounded off nearest hundred as $600$. Therefore, the smallest number is $550$.


Hence, the smallest number which when rounded off to the nearest hundred as $600$ is $550$.

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Mark the correct alternative of the following.
$1827$ when rounded off to be nearest hundred is?

  1. $1900$
  2. $1820$
  3. $1850$
  4. $1800$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Rounding a number to the nearest hundred, we use the following rules:

A) We round the number up to the nearest hundred if the last two digits in the number are $50$ or above.

B) We round the number down to the nearest hundred if the last two digits in the number are $49$ or below.

C) If the last two digits are $00$, then we do not have to do any rounding, because it is already to the hundred.

Now, we are given a number $1827$ whose hundred place is $27$ which is below $50$, therefore, the nearest hundred to $1827$ is $1800$.

Hence, the nearest hundred of $1827$ when rounded off is $1800$.
Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round off to nearest thousands. The given number is 76,823

  1. $76,000$
  2. $75,000$
  3. $77,000$
  4. $78,000$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The given number is $76823$. The one's place of the number is $3$, the tens place is $2$, the hundreds place is $8$ and the thousands place is $6$.

Its digit at hundreds place is $8$, which is greater than $5$. 

So, we increase the digit at thousands place by $1$ and replace each one of the digits at hundreds, tens and ones place by $0$ to get the rounded off numbers that is the number $76823$ is rounded off to nearest thousands as $77000$.

Hence, the number $76823$ is rounded off to the nearest thousands as $77000$.
Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round off to nearest thousands. The given number is 24,500

  1. $24,400$
  2. $24,600$
  3. $25,000$
  4. $24,000$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The given number is $24,500$. The one's place of the number is $0$, the tens place is $0$, the hundreds place is $5$ and the thousands place is $4$.

Its digit at hundreds place is $5$.

So, we increase the digit at thousands place by $1$ and replace each one of the digits at hundreds, tens and ones place by $0$ to get the rounded off numbers that is the number $24,500$ is rounded off to nearest thousands as $25,000$.

Hence, the number $24,500$ is rounded off to the nearest thousands as $25000$.
Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

 Round off $690$ to nearest $100$.

  1. $780$
  2. $690$
  3. $700$
  4. $800$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\Rightarrow$  The given number is $690$

$\Rightarrow$  Its tens digit are $9$, which is greater than $5$. 
$\Rightarrow$  So, we increase the digits at hundreds place by $1$ and replace each one of the digits at tens and ones place by $0$ to round off the given number to nearest $100$.
$\therefore$   Round off $690$ to nearest $100$ is $700.$

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round off to the nearest $10, 100,$ and $1000$:
$1289$

  1. $1290,1389,1009$
  2. $1290,1300,1000$
  3. $1280, 1300, 1200$
  4. $1280,1200,1000$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\Rightarrow$  Round off to 10 for 1289 is 1280 or 1290 but nearest to 1289 is 1290.

$\Rightarrow$  So, round off to the nearest $10$ is $1290$.
$\Rightarrow$  Round off to 100 for 1289 is 1200 or 1300 but nearest to 1289 is 1300.
$\Rightarrow$  So, round off to the nearest $100$ is $1300$.

$\Rightarrow$  Round off to 1000 for 1289 is 1000 or 2000 but nearest to 1289 is 1000.
$\Rightarrow$  So, round off to the nearest $1000$ is $1000$.

$\therefore$  The answer is $1290,\,1300,\,1000.$

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Round-off $13$ to nearest $10$.

  1. $10$
  2. $20$
  3. $13$
  4. $1$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\Rightarrow$  The given number is $13$

$\Rightarrow$   Its unit digit is $3$ which is less than 5.
$\Rightarrow$   So, we replace unit digit by $0$ keep the other digits as they are to round off the given number to nearest $10$
$\therefore$   Round-off 13 to nearest 10 is $10$.

Multiple choice maths mental arithmetic estimation and rounding off estimations, bounds and rounding off rounding off numbers rounding of decimals

Rohit's teacher asked him to tell the correct answer after performing the steps given.
$\bullet$ Round off $43, 98$ and $250$ to nearest tens.
$\bullet$ After rounding off, add them.
$\bullet$ Round off the sum to the nearest hundreds.
Then, the correct answer is __________.

  1. $300$
  2. $400$
  3. $350$
  4. $480$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Rounding off to nearest tens:

If unit digit is $0,1,2,3,4$ then round down to nearest tens.
If unit digit is $5,6,7,8,9$ then, round up to nearest tens.
$43$ $\rightarrow$ $40$
$98$ $\rightarrow$ $100$
$250$ $\rightarrow$ $250$
$40+100+250$ $\rightarrow$ $390$
$390$  $\rightarrow$  $400$
Hence, Option B is correct.