Tag: multiplying decimals

Questions Related to multiplying decimals

What is the value of $7.854 \times 10$ ?

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $785.4$

  2. $78.54$

  3. $7854$

  4. $78540$

Show answer
Correct Option: B
Explanation:

$7.854$

  $\times 10$
$\overline{78.540}$

Hence, $7.854 \times 10 = 78.54$

Solve the following:

$0.05 \times 0.09 \times 5 $ 

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $0.025$

  2. $0.225$

  3. $0.005$

  4. $0.0225$

Show answer
Correct Option: D
Explanation:

$0.05 \times 0.09 \times 5$

$=0.05 \times 0.45$
$=0.0225$

$58.326 \times 463.9 \times 0.0081$ is same as 

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $5.8326 \times 4.639 \times 8.1$

  2. $5.8326 \times 4.639 \times 0.81$

  3. $58326 \times 4639 \times 0.0000081$

  4. None of these

Show answer
Correct Option: A
Explanation:

In option A,

$58.326\div10 = 5.8326$
$463.9\div100 = 4.639$
$0.0081\times1000 = 8.1$

Multiplication by $1000$ and Division by $10\times100 = 1000$ gives the same result.

Answer : $5.8326 \times 4.639 \times 8.1$

$5.\overline { 07 } \quad \times 10=y$, then the value of $y$ is

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $50.\overline { 07 } $

  2. $50.0\overline { 7 } $

  3. $50.7\overline { 07 } $

  4. $50.70$

Show answer
Correct Option: C
Explanation:

$5.\overline { 07 } \quad \times 10=50.7070707=50.7\overline { 07 } $

If we write November 8, 1988, as 8.11.88, we see $8\times11=88$. How many such days are in 1972?

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. 6

  2. 4

  3. 3

  4. 2

Show answer
Correct Option: A
Explanation:

Multiples of 72 = 2,4,6,8,9,12,18,24,36,72
But in a year we have only 12 months and in a month we have only 30 days
So We have
$24.3.72 = 24\times 3 = 72$
$18.4.72 = 18\times 4 = 72$
$12.6.72= 12\times6 = 72$
$9.8.72 = 9\times8 = 72$
$8.9.72 = 8\times 9 = 72$
$6.12.72 = 6\times 12 = 72$

$\displaystyle 0.04\times 0.08\times 4 $ is equal to

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $0.012$

  2. $0.128$

  3. $0.00128$

  4. $0.0128$

Show answer
Correct Option: D
Explanation:

The rule of thumb in multiplying decimal numbers is we'll count the decimals from the right-hand side and the total places in the decimal in the question will be in the answer.


Example $0.04$ has $2$ places decimal and $0.08$ also has $2$ places. So the total places are $4$. 

The product will have a decimal $4$ places from the right.
$0.04×0.08×4=0.0128$

So option D is the correct answer.

Solve:

$\displaystyle 14.79\times 1000 $ is

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $14709$

  2. $14790$

  3. $1479$

  4. $147.9$

Show answer
Correct Option: B
Explanation:

$14.79\times 1000 = 14790$

Hence Option B

Solve:

$\displaystyle 0.126\times 100 $ is-

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $12.6$

  2. $0.126$

  3. $1.26$

  4. $126$

Show answer
Correct Option: A
Explanation:

$0.126\times100$

$ = (126\times100)/1000$
$=12.6$
Hence Option A

If 0.111 is approximately equal to $\frac {1}{9}$, then the approximate value of 0.777 is

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. $\frac {5}{9}$

  2. $\frac {7}{9}$

  3. $\frac {2}{9}$

  4. $\frac {1}{9}$

Show answer
Correct Option: B
Explanation:

$0.777=7\times 0.111$
$=7\times \frac {1}{9}=\frac {7}{9}$

The cost of 1 lit. of milk is Rs. 7.50 then the cost of 30.5 lit. of milk is

maths decimal fraction multiplying decimals multiplication of decimals multiplication of division of decimal fraction by whole number and decimal fraction

  1. Rs. 225.75

  2. Rs. 223.75

  3. Rs. 228.75

  4. none

Show answer
Correct Option: C
Explanation:

The cost of 1 lit. of milk is Rs. 7.50 .
The cost of 30.5 lit. of milk is 
$\displaystyle 7.50\times 30.5=Rs.228.75$