### Theory:

Let us consider $\frac{3}{4}$ and $-\frac{3}{4}$. First, let us plot  $\frac{3}{4}$.

• Here, the numerator $$3$$ is less than the denominator $$4$$.
• Then the positive rational number will be between $$0$$ and $$1$$.
• Now, let us draw a number line and plot $$1$$ and $$-1$$.
• Then the number $\frac{3}{4}$ has to lie somewhere between $$0$$ and $$1$$.
• Now we divide the length between $$0$$ and $$1$$ into equal parts.
• The Denominator gives us the number of equal parts($$4$$).
• It is $$4$$, so we divide it into $$4$$ equal parts.
• The numerator tells us the number of parts starting from zero.
• Here, it is $$3$$. So we mark the point $$3$$ parts away from the zero as shown in the below figure.

Similarly, $-\frac{3}{4}$ can be marked using the same procedure because $-\frac{3}{4}$ is the corresponding value of $\frac{3}{4}$.
• We know that it lies between $$0$$ and $$-1$$. So, we divide it into four equal parts and mark $$3$$ parts away from the zero, as shown in the below figure.