To subtract these two fractions, we need to find a common denominator.

The factors of 3 are 1 and 3, while the factors of 27 are 1, 3, 9, and 27. From this, the least common multiple of 3 and 27 is 27.

So the fraction with the denominator 27 equivalent to 4/3 is 36/27 (4 multiplied by 9). And the fraction with the denominator 27 equivalent to 20/27 is 20/27.

Therefore, the subtraction of the fractions is:

36/27 - 20/27 = 16/27

Thus, 4/3 - 20/27 equals 16/27.