Tag: maths

Questions Related to maths

Mark the correct alternative of the following.
The difference between the greatest and smallest numbers which when rounded off a number to the nearest tens as $540$, is?

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

  1. $10$

  2. $9$

  3. $8$

  4. $11$

Show answer
Correct Option: B
Explanation:
We know that the greatest number that when rounded off to the nearest tens will become $540 = 544$

Least number that when rounded off to the nearest tens will become $540 = 535$

So, the difference between them $= 544 − 535 = 9$

Hence, the difference between the greatest and smallest numbers which when rounded off a number to the nearest tens as $540$ is $9$.

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

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

  1. $550$

  2. $595$

  3. $604$

  4. $599$

Show answer
Correct Option: A
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 $550$.

Mark the correct alternative of the following.
The greatest number which when rounded off to the nearest thousand as $7000$, is?

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

  1. $6500$

  2. $6549$

  3. $7499$

  4. $6499$

Show answer
Correct Option: C
Explanation:

Numbers from $6500$ to $7499$ are rounded off to nearest thousand as $7000$. Therefore, the greatest number is $7499$.


Hence, the greatest number which when rounded off to the nearest thousand as $7000$ is $7499$.

Mark the correct alternative of the following.
The difference between the greatest and smallest numbers which when rounded off a number to the nearest hundred as $6700$, is?

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

  1. $100$

  2. $99$

  3. $98$

  4. $101$

Show answer
Correct Option: B
Explanation:
We know that the greatest number that when rounded off to the nearest hundred will become$ 6,700 = 6749$

Least number that when rounded off to the nearest hundred will become $6,700 = 6650$

So, the difference between them $= 6,749 − 6,650 = 99$

Hence, the difference between the greatest and smallest numbers which when rounded off a number to the nearest hundred as $6700$ is $99$.

Mark the correct alternative of the following.
$2985$ is rounded off to the nearest hundred and the nearest tens. The difference between the two values is?

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

  1. $5$

  2. $100$

  3. $10$

  4. $150$

Show answer
Correct Option: C
Explanation:
$2985$ estimated to the nearest hundred $= 3000$

$2985$ estimated to the nearest tens $=2990$

Now, the difference between the nearest hundred and nearest tens of $2985$ is:

$3000-2990=10$

Hence, the difference between the two values is $10$.

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

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

  1. $1900$

  2. $1820$

  3. $1850$

  4. $1800$

Show answer
Correct Option: D
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 $1800$.

Round off 11,125 to thousand place

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

  1. 11,000

  2. 12,000

  3. 11,120

  4. 1,100

Show answer
Correct Option: A
Explanation:
The given number is $11,125$. The ones place of the number is $5$, the tens place is $2$, the hundreds place is $1$ and the thousands place is $1$.

Its digit at hundreds place is $1$, which is less than 5. So, we replace each of the hundreds, tens and ones digits by $0$ and keep the other digits as they are.

Therefore, the number $11,125$ is rounded off to nearest thousands as $11,000$.

Hence, the number $11,125$ is rounded off to nearest thousands as $11,000$.

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

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

  1. $76,000$

  2. $75,000$

  3. $77,000$

  4. $78,000$

Show answer
Correct Option: C
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 $77000$.

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

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

  1. $24,400$

  2. $24,600$

  3. $25,000$

  4. $24,000$

Show answer
Correct Option: C
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 $25000$.

Find the product of 5 and the difference between 328 tenths and 4587 thousandths. Round off your answer to 1 decimal place. 

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

  1. $146.9$

  2. $141.1$

  3. $139.2$

  4. $140.2$

Show answer
Correct Option: B
Explanation:
Here we want to find a product of $5$ and the difference between $328$ tenths and $4587$ thousandths.

So,
First we find tenth of $328 = \dfrac {328}{10}  =  32.8$
And
Thousandths of $4587  = \dfrac {4587}{1000}  =  4.587$

And difference between them  $=  32.8  - 4.587  = 28.213$

Now product of $5$ and the difference between $328$ tenths and $4587$ thousandths  $=  5\times 28.213  = 141.065$

And we know that if the hundredths places are fifty or more, the tenths place is increased by one.

Hence, round off answer to 1 decimal place is $141.1$