Tag: multiplication and division of decimals

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Questions Related to multiplication and division of decimals

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

If $\dfrac { 144 }{ 0.144 } =\dfrac { 14.4 }{ x } $, then the value of $x$ is:

  1. $0.0144$
  2. $1.44$
  3. $14.4$
  4. $144$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\dfrac { 144 }{ 0.144 } =\dfrac { 14.4 }{ x } $

$\Rightarrow \dfrac { 144\times 1000 }{ 144 } =\dfrac { 14.4 }{ x } $

$\Rightarrow x=\dfrac { 14.4 }{ 1000 } =0.0144$

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

$0.75$ of a number is $1200$. What is $\displaystyle\frac{5}{8}$ of that number?

  1. $1000$
  2. $1060$
  3. $880$
  4. $8002$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the required number be $x$
According to question, we have
$0.75$ of $x$ $=1200$
$\Rightarrow \displaystyle\frac{75}{100}\times x=1200$
$\Rightarrow \displaystyle x=1200\times \frac{100}{75}=1600$
Therefore, required number is $1600$.
Now, $\displaystyle\frac{5}{8}$ of the number $=\displaystyle\frac{5}{8}\times 1600=1000$.

Thus the required number is $1000$.

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

Solve for $x$:

$35.453 =\dfrac{34.968x+ 36.956(100- x)}{100}$

  1. $7.56$
  2. $756$
  3. $75.6$
  4. $0.756$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\\35.453\times 10=34.968x+36.956(100-x)\\ 3545.3=(34.968-36.956)x+3695.6\\\therefore x=(\frac{3545.3-3695.6}{34.968-36.956})\\ (\frac{-150.3}{-1.988})=75.6$

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

The value of $\dfrac{8492 \times 3.72}{47.8 \times 52.24}$ is

  1. $1.265$
  2. $14.75$
  3. $1.475$
  4. $12.65$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Performing the arithmetic computation by estimating or multiplying the numerator and dividing by the product of the denominator values yields approximately 12.65. Precise calculation confirms this decimal value.

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

$\displaystyle \frac{24.23\times 1.423\times 34.21}{521.3\times 413.32\times 2.53}$ is same is 

  1. $\displaystyle \frac{2423\times 1423\times 3421}{5213\times 41332\times 253}$
  2. $\displaystyle \frac{2423\times 1423\times 3421}{5213\times 4133.2\times 2.53}$
  3. $\displaystyle \frac{2.423\times 14.23\times 342.1}{521.3\times 4133.2\times 2.53}$
  4. $\displaystyle \frac{24.23\times 14.23\times 3.421}{5.213\times 41332\times 0.253}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Option c is correct answer.

 
As in that expression total numbers after decimal is same as the given expression.


$\displaystyle \frac{24.23\times 1.423\times 34.21}{521.3\times 413.32\times 2.53}$  $=\displaystyle \frac{2.423\times 14.23\times 342.1}{521.3\times 4133.2\times 2.53}$

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

Simplify : $\displaystyle \frac{3.6\times 0.48\times 2.50}{0.12\times 0.09\times 0.5}$

  1. 80

  2. 800

  3. 8000

  4. 80,000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\displaystyle \frac{3.6\times 0.48\times 2.50}{0.12\times 0.09\times 0.5}=\frac{36\times 48\times 250}{12\times 9\times 5}=800 $


No of decimal places in num and den being equal

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

Which number is equal to
$\left ( \displaystyle \frac {0.1}{0.01}\, +\, \displaystyle \frac {0.01}{0.1} \right )\, ?$

  1. $10.1$
  2. $1.10$
  3. $1.01$
  4. $10.01$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let us first write the decimals as fractions as follows:


$0.1=\dfrac { 1 }{ 10 } \ 0.01=\dfrac { 1 }{ 100 }$ 

Now, the given expression $\dfrac { 0.1 }{ 0.01 } +\dfrac { 0.01 }{ 0.1 }$ can be solved as follows:
 
$\dfrac { 0.1 }{ 0.01 } +\dfrac { 0.01 }{ 0.1 } =\dfrac { \dfrac { 1 }{ 10 }  }{ \dfrac { 1 }{ 100 }  } +\dfrac { \dfrac { 1 }{ 100 }  }{ \dfrac { 1 }{ 10 }  } =\dfrac { \dfrac { 1 }{ 1 }  }{ \dfrac { 1 }{ 10 }  } +\dfrac { \dfrac { 1 }{ 10 }  }{ \dfrac { 1 }{ 1 }  } =10+\dfrac { 1 }{ 10 } =\dfrac { (10\times 10)+1 }{ 10 } =\dfrac { 100+1 }{ 10 } =\dfrac { 101 }{ 10 } =10.1$

Hence, $\dfrac { 0.1 }{ 0.01 } +\dfrac { 0.01 }{ 0.1 }=10.1$

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

Simplify : $\displaystyle \frac{0.2\times0.2+0.2\times0.02}{0.044}$

  1. $0.4$
  2. $0.2$
  3. $0.1$
  4. $1$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

We will first convert the decimals into fraction in the given fraction and then solve it as follows:


$\dfrac { 0.2\times 0.2+0.2\times 0.02 }{ 0.044 } =\dfrac { \left( \dfrac { 2 }{ 10 } \times \dfrac { 2 }{ 10 }  \right) +\left( \dfrac { 2 }{ 10 } \times \dfrac { 2 }{ 100 }  \right)  }{ \dfrac { 44 }{ 1000 }  } =\dfrac { \dfrac { 4 }{ 100 } +\dfrac { 4 }{ 1000 }  }{ \dfrac { 44 }{ 1000 }  } =\dfrac { \dfrac { 40+4 }{ 1000 }  }{ \dfrac { 44 }{ 1000 }  } =\dfrac { \dfrac { 44 }{ 1000 }  }{ \dfrac { 44 }{ 1000 }  } =1$

Hence, $\dfrac { 0.2\times 0.2+0.2\times 0.02 }{ 0.044 } =1$