Tag: decimal numbers

Quizzes (12) Questions (85)

Questions Related to decimal numbers

Multiple choice maths decimal numbers adding and subtracting decimals addition and subtraction of decimals operations on decimals

The value of $\displaystyle \frac{0.25\times0.25-0.24\times0.24}{0.49}=?$

  1. $0.0006$
  2. $0.49$
  3. $0.01$
  4. $0.1$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given, $\displaystyle \frac {0.25\times0.25-0.24\times0.24}{0.49}$

Using the identity $a^2 - b^2 = (a+b)(a-b)$
$\therefore \displaystyle 0.25\times 0.25 - 0.24\times 0.24 = (0.25+0.24)(0.252-0.24) = (0.49)(0.01)$

Thus, $\displaystyle \frac {0.25\times0.25-0.24\times0.24}{0.49} = \frac {0.49\times 0.01}{0.49}$ = $0.01$

Multiple choice maths decimal numbers adding and subtracting decimals addition and subtraction of decimals operations on decimals

$\displaystyle \frac{42.31-26.43}{42.31+26.43}\div \frac{423.1-264.3}{4.231+2.643}$  is equal to 

  1. $\displaystyle 10^{-2}$
  2. $\displaystyle 10^{-1}$

  3. 10
  4. $\displaystyle 10^{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\displaystyle \frac{42.31-26.43}{42.31+26.43}\div \frac{423.1-264.3}{4.231+2.643}$

$=\displaystyle \frac{15.88}{68.74}\div \frac{158.8}{6.874}$
$=\displaystyle \frac{15.88}{68.74}\times \frac{6.874}{158.8}=\frac{1588}{6874}\times \frac{68.74}{1588}$
= $\displaystyle \frac{68.74}{6874}=\frac{6874}{687400}=\frac{1}{100}=0.01$

Multiple choice maths decimal numbers adding and subtracting decimals addition and subtraction of decimals operations on decimals

Which pair of operations will make the equation below true when inserted into the blank spaces in the order shown? $\displaystyle 2\frac{3}{10} $      $1.5$  _  $2=1.8$

  1. $-$ and $+$
  2. $\displaystyle \times $ and $+$
  3. $+$ and $-$
  4. $\displaystyle \times $and $-$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let us first write the mixed fraction $2\dfrac {3}{10}$ in decimals as follows:


$2\dfrac { 3 }{ 10 } =\dfrac { (2\times 10)+3 }{ 10 } =\dfrac { 20+3 }{ 10 } =\dfrac { 23 }{ 10 } =2.3$

Therefore, $2\dfrac {3}{10}=2.3$

Now, add $1.5$ to $2.3$ then we get,

$2.3+1.5=3.8$

Now subtract $2$ from $3.8$ as follows:

$3.8-2=1.8$

Therefore, we have $2.3+1.5-2=1.8$

Hence, $2\dfrac { 3 }{ 10 } +1.5-2=1.8$

Multiple choice maths decimal numbers adding and subtracting decimals addition and subtraction of decimals operations on decimals

In the expression $24 - [ 2.4 - { 0.24 - (0.024 - x)}] = 21.8184$, the value of x is 

  1. $0.0024$
  2. $0.024$
  3. $0.24$
  4. $2.4$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

We solve the given expression as follows:


$24−\left[ 2.4−{ \left{ 0.24−\left( 0.024−x \right)  \right}  } \right] =21.8184\ \Rightarrow 24−\left[ 2.4−{ \left{ 0.24−0.024+x \right}  } \right] =21.8184\ \Rightarrow 24−\left[ 2.4−{ \left{ 0.216+x \right}  } \right] =21.8184\ \Rightarrow 24−\left[ 2.4−{ 0.216-x } \right] =21.8184$
$\Rightarrow 24−\left[ 2.184-x \right] =21.8184\ \Rightarrow 24−2.184+x=21.8184\ \Rightarrow 21.816+x=21.8184\ \Rightarrow x=21.8184-21.816\ \Rightarrow x=0.0024$

Hence, $x=0.0024$

Multiple choice maths decimal numbers adding and subtracting decimals addition and subtraction of decimals operations on decimals

The simplification of $\displaystyle3\overline{36}-2.\overline{05}+1\overline{33}$ is equal to

  1. 2.6

  2. 2.64
  3. $\displaystyle 2.\overline{61}$
  4. $\displaystyle 2.\overline{64}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\displaystyle 3.\overline{36}-2.\overline{05}+1.\overline{33}$


= $\displaystyle 3+0.\overline{36}-\left ( 2+0.\overline{05} \right )+1+0.\overline{33}$

= $\displaystyle 3+\frac{36}{99}-2-\frac{5}{99}+1+\frac{33}{99}$


= $\displaystyle 2+\frac{64}{99}=2+0.\overline{64}=2.\overline{64}$

Multiple choice maths decimal numbers adding and subtracting decimals addition and subtraction of decimals operations on decimals

If k is an integer and $\displaystyle \left( 0.0025 \right) \left( 0.025 \right) \left( 0.00025 \right) \times { 10 }^{ k }$ is an integer, what is the least possible value of k ?

  1. -12

  2. -6

  3. 0

  4. 6

  5. 12
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Given expression:

 $(25 \times 10^{-4}) $ $(25 \times 10^{-3}) $$(25 \times 10^{-5}) $
$\rightarrow$ $15625 \times 10^{-12}$.
So, to make the result an integer, we must multiply by $10^{12}$
Least possible value of k should be 12. (option E)

Multiple choice maths decimal numbers adding and subtracting decimals addition and subtraction of decimals operations on decimals

Match the following.

Column I Column II
(i) $715+12.59+685.35=$ (P) $417.16$
(ii) $518-( 216.80 -115.96 )=$ (Q) $213.07$
(iii) $4.090+0.050+6.500=$ (R) $1412.94$
(iv) $36.050+198.05-21.03=$ (S) $10.640$
  1. (i)$\rightarrow$ (Q), (ii) $\rightarrow$ (R), (iii)$\rightarrow$ (S), (iv) $\rightarrow$ (P)
  2. (i)$\rightarrow$ (R), (ii) $\rightarrow$ (P), (iii) $\rightarrow$(S), (iv) $\rightarrow$(Q)
  3. (i)$\rightarrow$ (R), (ii)$\rightarrow$(S), (iii) $\rightarrow$ (P), (iv) $\rightarrow$ (Q)
  4. (i)$\rightarrow$ (Q), (ii) $\rightarrow$(S), (iii) $\rightarrow$ (P), (iv)$\rightarrow$(R)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

(I) $715+12.59+685.35=1412.94$
(II) $518-(216.80-115.96)=518-100.84=417.16$
(III) $4.090+0.050+6.500=10.640$
(IV) $36.050+198.05-21.03=213.07$.