A fraction is written in terms of two parts: the number on top is called the numerator and the number on the bottom is called the denominator. We can use the division method to solve this question. To get a decimal, simply divide the numerator 81 by the denominator 20:
81 (numerator) ÷ 20 (denominator) = 4.05
As a result, you get 4.05 as your answer when you convert 4 1/20 (or 81/20) to a decimal.