Which one is the biggest between 1/2 and 1/4

The denominators are 2 and 4. The least common multiple of 2 and 4 is 4.

The fraction $\frac{1}{4}$ already has a denominator of 4.
For $\frac{1}{2}$, multiply the numerator and denominator by 2 to get a denominator of 4:

Now we compare $\frac{2}{4}$ and $\frac{1}{4}$.
Since the denominators are the same, we compare the numerators.

Therefore,

Since $\frac{2}{4}$ is equivalent to $\frac{1}{2}$, we can conclude: