Tag: maths

Questions Related to maths

$\displaystyle \frac{\left ( 2.3 \right )^{3}-0.027}{\left ( 2.3 \right )^{2}+0.69+0.09}=? $

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. $2.6$

  2. $2$

  3. $2.33$

  4. $2.8$

Show answer
Correct Option: B
Explanation:
$\dfrac { { \left( 2.3 \right)  }^{ 3 }-0.027 }{ { \left( 2.3 \right)  }^{ 2 }+0.69+0.09 } \\ =\dfrac { 12.167-0.027 }{ 5.29+0.69+0.09 } \\ =\dfrac { 12.14 }{ 6.07 } \\ =2$
So, correct answer is option B.

$58+\cfrac{3}{100}+\cfrac{7}{1000}=..........$

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. $58.0037$

  2. $58.37$

  3. $58.037$

  4. none of these

Show answer
Correct Option: C
Explanation:

$58+\cfrac{3}{100}+\cfrac{7}{1000}$
$=58+\cfrac{0}{10}+\cfrac{3}{100}+\cfrac{7}{1000}=58.037$

Which of the following is equal to $1$?

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. $\displaystyle \frac{(0.11)^{2}}{(1.1)^{2}\times 0.1}$

  2. $\displaystyle \frac{(1.1)^{2}}{11^{2}\times (0.01)^{2}}$

  3. $\displaystyle \frac{(0.011)^{2}}{1.1^{2}\times 0.01^2}$

  4. $\displaystyle \frac{(0.11)^{2}}{1.1^{2}\times 0.01}$

Show answer
Correct Option: C
Explanation:
$\Rightarrow \cfrac{(0.11)^{2}}{(1.1)^{2}\times 0.1}=\cfrac{0.0121}{1.21\times 0.1}=\cfrac{0.0121}{0.121}=0.1$

$\Rightarrow \cfrac{(1.1)^{2}}{11^{2}\times (0.01)^{2}}=\cfrac{1.21}{121\times 0.0001}=\cfrac{0.01}{0.0001}=100$

$\Rightarrow \cfrac{(0.011)^{2}}{(1.1)^{2}\times (0.01)^{2}}=\cfrac{0.000121}{1.21\times 0.0001}=1$

$\Rightarrow \cfrac{(0.11)^{2}}{1.1^{2}\times 0.01}=\cfrac{0.0121}{1.21\times 0.01}=\cfrac{0.0121}{1.21}=1.21$

$6$ thousandths is:

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. $0.06$

  2. $0.006$

  3. $6.000$

  4. $0.066$

Show answer
Correct Option: A
Explanation:

Place value chart of decimal number

Tenths Hundredths Thousandths
10 100 1000

If $\displaystyle 1420\div 1.42 =1000,$ then $142.0\div 14.2 =$ 

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. $1$

  2. $10$

  3. $0.10$

  4. $1000$

Show answer
Correct Option: B
Explanation:

$\displaystyle \frac { 142.0 }{ 14.2 } = \frac { 142.0 }{ 14.2 }\times \frac { 10 }{ 10 } = \frac { 1420 }{ 142 }=10 $

Product of 68.12and 2.5 is -

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. 170.3

  2. 1703

  3. 1.703

  4. 17.03

Show answer
Correct Option: A
Explanation:

(68.12)*(2.5)=170.3

If $2805\div 2.55=1100$, then $280.5\div 25.5= ...........$

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. 1.1

  2. 1.01

  3. 0.11

  4. 11

Show answer
Correct Option: D
Explanation:

$\frac {280.5}{25.5}=\frac {280.5}{25.5}\times \frac {10}{10}\times \frac {10}{10}$
$=\frac {2805}{2.55}\times \frac {1}{100}=\frac {1100}{100}=11$

$2\times 0.5+9\div 0.3+10\times 0.92= ...........$

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. 33.0

  2. 40.2

  3. 6.0

  4. 31.2

Show answer
Correct Option: B
Explanation:

By BODMAS rule,
$2\times 0.5+9\div 0.3+10\times 0.92$
$=2\times 0.5+30+10\times 0.92$
$=1.0+30+9.2$
$=40.2$

If $29\times 27=783$; then $0.29\times 0.27= ...............$

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. 0.0783

  2. 0.783

  3. 78.3

  4. 7.83

Show answer
Correct Option: A
Explanation:

$0.29\rightarrow 2$ decimal places
$0.27\rightarrow 2$ decimal places
$\therefore 0.29\times 0.27=0.0783$
$(2+2=4$ decimal places)

Find the value of $1000(1+0.1+0.01+0.001).$

maths calculations and mental strategies 4 mental additions and subtractions of decimals multiplication and division of decimals mental multiplication and division

  1. 1.111

  2. 1.11

  3. 111.1

  4. 1111

Show answer
Correct Option: D
Explanation:

$1.000$
$+0.100$
$+0.010$
$\underline {+0.001}$
$\underline {1.111}$
$\Rightarrow 1.111\times 1000=1111$