MCQ Questions for Class 8 Maths Rational Numbers Quiz 10

Find

\frac{2}{5} \times \frac{- 3}{7} - \frac{1}{14} - \frac{3}{7} \times \frac{3}{5}

$\dfrac { 2 }{ 5 } \times \dfrac { -3 }{ 7 } -\dfrac { 1 }{ 14 } -\dfrac { 3 }{ 7 } \times \dfrac { 3 }{ 5 }$

0%
$2$
0%
$\dfrac { 1 }{ 2 }$
0%
$-2$
0%
$\dfrac { -1 }{ 2 }$

State which property is used in following operation-

$\dfrac { -19 }{ 29 } \times \dfrac { 29 }{ -19 } =1$

0%
Additive inverse
0%
multiplicative inverse
0%
commutative
0%
Associative

Name the property which is used in following operation-

$\dfrac { -4 }{ 5 } \times 1=1\times \dfrac { -4 }{ 5 } =\dfrac { -4 }{ 5 }$

0%
Distributive
0%
Associative
0%
Commutative
0%
None of the above

Find the value of following expression-

$\dfrac { -4 }{ 5 } \times \dfrac { 3 }{ 7 } \times \dfrac { 15 }{ 16 } \times \dfrac { -14 }{ 9 }$

0%
$\dfrac { 1 }{ 2 }$
0%
$\dfrac { 1 }{ 4 }$
0%
$\dfrac { 1 }{ 3 }$
0%
$\dfrac { 3 }{ 4 }$

Solve

$\dfrac { 2 }{ 5 } \times \left( \dfrac { -3 }{ 7 } \right) -\dfrac { 1 }{ 6 } \times \dfrac { 3 }{ 2 } +\dfrac { 1 }{ 14 } \times \dfrac { 2 }{ 5 }$

0%
$\dfrac { 28 }{ 11 }$
0%
$\dfrac { 11 }{ 28 }$
0%
$\dfrac { -28 }{ 11 }$
0%
$\dfrac { -11 }{ 28 }$

Find the additive inverse of

$\dfrac { -7 }{ 9 }$

0%
$\dfrac { -9 }{ 7 }$
0%
$\dfrac { 7 }{ 9 }$
0%
$\dfrac { 9 }{ 7 }$
0%
$0$

For any two real number, an operation defined by

$a* b= 1 +ab$ is.

0%
Commutative but not associative
0%
Associative but not commutative
0%
Neither Commutative nor associative
0%
Both commutative and associative

Explanation

A binary operation

$∗$ on

$A$ is associative if

$∀a, b, c ∈ A$ ,

$(a ∗ b) ∗ c = a ∗ (b ∗ c)$ and

A binary operation

$∗$ on

$A$ is commutative if

$∀a, b ∈ A$ ,

$a ∗ b = b ∗ a$

$a∗b=1+ab$ is commutative as:

$a∗b=b∗a\\ \Rightarrow 1+ab =1+ba \\ \Rightarrow 1+ab =1+ab$

which is true.

$a∗b=1+ab$ is not associative as:

$(a∗b)∗c=a∗(b∗c)\\ \Rightarrow \left( 1+ab \right) ∗c=a∗\left( 1+bc \right) \\ \Rightarrow 1+(1+ab)c=1+a(1+bc)\\ \Rightarrow 1+c+abc=a+a+abc$

which is not true.

Hence, the binary operation

$∗$ is commutative but not associative.

What is the multiplicative inverse of

$\dfrac { 8 }{ 21 } ?$

0%
$-\frac { 8 }{ 21 }$
0%
1
0%
0
0%
$\frac { 21 }{ 8 }$

State whether the statements are true (T) or false (F).
If

$\dfrac{x}{y}$ is the additive inverse of

$\dfrac{c}{d},$ then

$\dfrac{x}{y} - \dfrac{c}{d} = 0.$

0%
True
0%
False

The value of $$\left( \sqrt { 2 } +1 \right) ^{ 6 }+\left( \sqrt { 2 } -1 \right) ^{ 6 }$4

0%
99
0%
182
0%
196
0%
198

State whether the statements are true (T) or false (F).
The additive inverse of

$\dfrac{1}{2}$ is

$-2.$

0%
True
0%
False

An example of a rational number between

$\sqrt { 2 }$ and

$\sqrt { 15 }$ is

0%
3.9
0%
2.6
0%
$\dfrac { \sqrt { 2 } +\sqrt { 15 } }{ 2 }$
0%
$\dfrac { \sqrt { 2 } X\sqrt { 15 } }{ 2 }$

which of the following is the insertion of three fractions in between

$\frac{7}{{12}}$ and

$\frac{9}{{10}}$ ?

0%
$\frac{8}{{11}},\frac{{15}}{{28}},\frac{{17}}{{21}}$
0%
$\frac{4}{9},\frac{{23}}{{25}},\frac{7}{{24}}$
0%
$\frac{{11}}{{18}},\frac{5}{{12}},\frac{{17}}{{19}}$
0%
$\frac{{8}}{{11}},\frac{15}{{23}},\frac{{17}}{{21}}$

State whether the statements are true (T) or false (F).
If

$\dfrac{x}{y}$ is the additive inverse of

$\dfrac{c}{d},$ then

$\dfrac{x}{y} + \dfrac{c}{d} = 0.$

0%
True
0%
False

State whether the statement is true (T) or false (F).
If

$x + y = 0,$ then

$-y$ is known as the negative of x, where x and y are rational numbers.

0%
True
0%
False

State whether the statements are true (T) or false (F).
Subtraction of rational number is commutative.

0%
True
0%
False

State whether the statements are true (T) or false (F).
For all rational numbers

$a, b$ and

$c, a (b + c) = ab + bc.$

0%
True
0%
False

State whether the statements are true (T) or false (F).
If x and y are negative rational numbers, then so is

$x + y.$

0%
True
0%
False

State whether the statements are true (T) or false (F).
The negative of the negative of any rational number is the number itself.

0%
True
0%
False

CBSE Questions for Class 8 Maths Rational Numbers Quiz 10 - MCQExams.com

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Practice Class 8 Maths Quiz Questions and Answers

CBSE Questions for Class 8 Maths Rational Numbers Quiz 10 - MCQExams.com

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Practice Class 8 Maths Quiz Questions and Answers

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