Tag: adding and subtracting decimals

Questions Related to adding and subtracting decimals

The base of the decimal number system is ten, meaning, for example, that 123=1.10$^{2}$ + 2.10 + 3.
In the binary system, which has base two, the first five positive integers are 1,10,11,100,101. The numeral 10011 in the binary system would then be written in the decimal system as:

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

  1. 19

  2. 40

  3. 10011

  4. 11

  5. 7

Show answer
Correct Option: A
Explanation:

binary(10011)= (1)*2^4 + (0)*2^3 + (0)*2^2 + (1)*2^1 + (1)*2^0

                     =16 + 0 + 0 + 2 + 1
                     =19.

If $1.8 - 6.3x = -0.3x$, then find the value of $x$ is


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

  1. $x=0.3$

  2. $x=0.6$

  3. $x=0.7$

  4. $x=0.5$

Show answer
Correct Option: A
Explanation:

from question 

$1.8-6.3x=-0.3x$

$\Rightarrow6.3x -0.3x =1.8$

$\Rightarrow6.0x =1.8$

$\Rightarrow x =\dfrac{1.8}{6}$

$x = 0.3$

$\text{Option A is correct.}$

Evaluate: $3.7-1.9$

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

  1. $0.6$

  2. $7.3$

  3. $3.4$

  4. $1.8$

Show answer
Correct Option: D
Explanation:

$3.7-1.9$


$=\dfrac{37}{10}-\dfrac{19}{10}=\dfrac{37-19}{10}$


$=\dfrac{18}{10}=1.8$

Sum of $0.5, 12.56$ and $0.003$ is:

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

  1. $13.063$

  2. $31.036$

  3. $12.063$

  4. $12.036$

Show answer
Correct Option: A
Explanation:

The sum of $0.5 ,12.56$ and $0.003$ is

$0.5+12.56+0.003$ $=13.063$ 
Hence, the answer is $13.063$.

The charges in a resort are shown.
Mr. Mohit drove to the resort with his wife and three children on Saturday at $1:30$p.m. They left the resort at $8$ p.m. How much did Mr. Mohit and his family have to pay in all?

Entrance Fee Rs. $40$ per car
Monday to Friday Rs. $15.50$ per passenger
Saturday and Sunday Rs. $22.50$ per passenger
Parking charges Rs. $10.60$ per half hour


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

  1. Rs. $250.30$

  2. Rs. $300.90$

  3. Rs. $267.80$

  4. Rs. $290.30$

Show answer
Correct Option: D
Explanation:

Total number of members in family $\rightarrow$ $5$

Time they spent at the resort $\rightarrow$ $6.5$ hr
Entrance fee $\rightarrow$ $40$
Charge of the members $\rightarrow$  ($22.5$$\times$$5$) $\rightarrow$ $112.5$
Parking charges $\rightarrow$ ($13$$\times$$10.60$) $\rightarrow$ $137.80$ (we took $13$ Since charges are given for half an hour)
Total amount to be paid $\rightarrow$ $40$ + $112.5$ + $137.80$ $\rightarrow$ $290.30$
Hence, Option D is correct answer.