The most accurate way to estimate 33% of 52 is explained as follows:
To find a percentage, we calculate it as follows:
a% of b

Now, lets convert 33% into fraction first:
33%

Now,

We have two ways to calculate the same so we will compare the values of them and figure out which gives a value nearer to our actual value:
So,
and

We can see that the first method gives us a value which is far closer to the actual value.
Therefore,
is the most accurate way to estimate 33% of 52.