Replace '$\boxed{\phantom{653}}$' in each of the following by the correct number:

(i) $\dfrac{2}{3} = \dfrac{\boxed{\phantom{653}}}{15}$

(ii) $\dfrac{7}{18} = \dfrac{42}{\boxed{\phantom{653}}}$

(iii) $\dfrac{4}{\boxed{\phantom{653}}} = \dfrac{12}{15}$

(iv) $\dfrac{\boxed{\phantom{653}}}{11} = \dfrac{70}{154}$

(i) $\dfrac{2}{3} = \dfrac{\boxed{\phantom{653}}}{15}$

To get 15 from 3, we have to multiply 3 by 5.

So, multiply both numerator and denominator by 5.

$\Rightarrow \dfrac{2}{3} = \dfrac{2 \times 5}{3 \times 5} \\[1em] = \dfrac{10}{15}.$

Hence, replace $\boxed{\phantom{653}}$ by 10.

(ii) $\dfrac{7}{18} = \dfrac{42}{\boxed{\phantom{653}}}$

To get 42 from 7, we have to multiply 7 by 6.

So, multiply both numerator and denominator by 6.

$\Rightarrow \dfrac{7}{18} = \dfrac{7 \times 6}{18 \times 6} \\[1em] = \dfrac{42}{108}.$

Hence, replace $\boxed{\phantom{653}}$ by 108.

(iii) $\dfrac{4}{\boxed{\phantom{653}}} = \dfrac{12}{15}$

To get 4 from 12, we have to divide 12 by 3.

So, divide both numerator and denominator by 3.

$\Rightarrow \dfrac{12}{15} = \dfrac{12 \div 3}{15 \div 3} \\[1em] = \dfrac{4}{5}.$

Hence, replace $\boxed{\phantom{653}}$ by 5.

(iv) $\dfrac{\boxed{\phantom{653}}}{11} = \dfrac{70}{154}$

To get 11 from 154, we have to divide 154 by 14.

So, divide both numerator and denominator by 14.

$\Rightarrow \dfrac{70}{154} = \dfrac{70 \div 14}{154 \div 14} \\[1em] = \dfrac{5}{11}.$

Hence, replace $\boxed{\phantom{653}}$ by 5.