SECTION - D (5 MARKS)

9.

(i) Find three rational numbers between [tex]\frac{3}{7}[/tex] and [tex]\frac{2}{3}[/tex].

(ii) Find [tex]\frac{3}{7} + \left( -\frac{6}{11} \right) + \left( -\frac{8}{21} \right) + \frac{5}{22}[/tex].

(iii) Represent [tex]-\frac{2}{11}, -\frac{5}{11}, -\frac{9}{11}[/tex] on the number line.

(iv) What should be added to [tex]-\frac{16}{3}[/tex] to make it [tex]\frac{1}{9}[/tex]?

(v) What is the additive inverse of [tex]\frac{3}{5}[/tex]?



Answer :

Certainly! Let's tackle each part of the question step-by-step:

### (i) Find three rational numbers between [tex]\( \frac{3}{7} \)[/tex] and [tex]\( \frac{2}{3} \)[/tex]

To find three rational numbers between [tex]\( \frac{3}{7} \)[/tex] and [tex]\( \frac{2}{3} \)[/tex], we convert these fractions to like fractions with a common denominator. The least common multiple (LCM) of 7 and 3 is 21.

[tex]\[ \frac{3}{7} = \frac{3 \times 3}{7 \times 3} = \frac{9}{21} \][/tex]

[tex]\[ \frac{2}{3} = \frac{2 \times 7}{3 \times 7} = \frac{14}{21} \][/tex]

Now, we choose three rational numbers between [tex]\( \frac{9}{21} \)[/tex] and [tex]\( \frac{14}{21} \)[/tex]:

[tex]\[ \frac{10}{21}, \frac{11}{21}, \frac{12}{21} \][/tex]

So the three rational numbers are:

[tex]\[ \frac{10}{21} \approx 0.476, \quad \frac{11}{21} \approx 0.524, \quad \frac{12}{21} \approx 0.571 \][/tex]

### (ii) Find [tex]\( \frac{3}{7} + \left( -\frac{6}{11} \right) + \left( -\frac{8}{21} \right) + \frac{5}{22} \)[/tex]

To add these fractions, we first find a common denominator. The least common multiple of 7, 11, 21, and 22 is 462.

We convert each fraction to have the common denominator:

[tex]\[ \frac{3}{7} = \frac{3 \times 66}{7 \times 66} = \frac{198}{462} \][/tex]

[tex]\[ -\frac{6}{11} = \frac{-6 \times 42}{11 \times 42} = \frac{-252}{462} \][/tex]

[tex]\[ -\frac{8}{21} = \frac{-8 \times 22}{21 \times 22} = \frac{-176}{462} \][/tex]

[tex]\[ \frac{5}{22} = \frac{5 \times 21}{22 \times 21} = \frac{105}{462} \][/tex]

Adding these fractions:

[tex]\[ \frac{198}{462} + \frac{-252}{462} + \frac{-176}{462} + \frac{105}{462} = \frac{198 - 252 - 176 + 105}{462} = \frac{-125}{462} \approx 0.0038 \][/tex]

### (iii) Represent [tex]\( -\frac{2}{11}, -\frac{5}{11}, -\frac{9}{11} \)[/tex] on the number line

To represent these fractions on the number line, we should note their approximate decimal values and place them accordingly between -1 and 0.

[tex]\[ -\frac{2}{11} \approx -0.182, \quad -\frac{5}{11} \approx -0.455, \quad -\frac{9}{11} \approx -0.818 \][/tex]

### (iv) What should be added to [tex]\( -\frac{16}{3} \)[/tex] to make it [tex]\( \frac{1}{9} \)[/tex]?

Let [tex]\( x \)[/tex] be the number we need to add to [tex]\( -\frac{16}{3} \)[/tex] to get [tex]\( \frac{1}{9} \)[/tex].

[tex]\[ -\frac{16}{3} + x = \frac{1}{9} \][/tex]

Solving for [tex]\( x \)[/tex]:

[tex]\[ x = \frac{1}{9} - \left( -\frac{16}{3} \right) = \frac{1}{9} + \frac{16}{3} \][/tex]

Convert [tex]\( \frac{16}{3} \)[/tex] to have a common denominator of 9:

[tex]\[ \frac{16}{3} = \frac{16 \times 3}{3 \times 3} = \frac{48}{9} \][/tex]

Now add the fractions:

[tex]\[ x = \frac{1}{9} + \frac{48}{9} = \frac{49}{9} \approx 5.444 \][/tex]

### (v) What is the additive inverse of [tex]\( \frac{3}{5} \)[/tex]?

The additive inverse of a number is the number that, when added to it, results in zero. For [tex]\( \frac{3}{5} \)[/tex]:

[tex]\[ \text{Additive Inverse} = -\frac{3}{5} = -0.6 \][/tex]

So the answers are:

[tex]\[ \begin{aligned} & (i) & \quad & \left( \frac{10}{21}, \frac{11}{21}, \frac{12}{21} \right) \approx (0.476, 0.524, 0.571) \\ & (ii) & \quad & 0.0038 \\ & (iii) & \quad & \text{Representing } -0.182, -0.455, -0.818 \text{ on the number line} \\ & (iv) & \quad & 5.444 \\ & (v) & \quad & -0.6 \\ \end{aligned} \][/tex]