If x is a positive rational number which is not a perfect square, then $-5\sqrt{x}$ is

1. a negative integer
2. an integer
3. a rational number
4. an irrational number

If x, y are both positive rational numbers, then $(\sqrt{x} + \sqrt{y})(\sqrt{x} - \sqrt{y})$ is

1. a rational number
2. an irrational number
3. neither rational nor irrational number
4. both rational as well as irrational number

The number obtained on rationalising the denominator of ${\dfrac{1}{\sqrt{7} - 2}}$ is

1. ${\dfrac{\sqrt{7} + 2}{3}}$

2. ${\dfrac{\sqrt{7} - 2}{3}}$

3. ${\dfrac{\sqrt{7} + 2}{5}}$

4. ${\dfrac{\sqrt{7} + 2}{45}}$

Without actual division, find whether the following rational numbers are terminating decimals or recurring decimals :

$\begin{matrix} \text{(i)} & \dfrac{13}{45} \\[1.5em] \text{(ii)} & -\dfrac{5}{56} \\[1.5em] \text{(iii)} & \dfrac{7}{125} \\[1.5em] \text{(iv)} & -\dfrac{23}{80} \\[1.5em] \text{(v)} & -\dfrac{15}{66} \\[1.5em] \end{matrix}$

In case of terminating decimals, write their decimal expansions.