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 129 by the denominator 40:
129 (numerator) ÷ 40 (denominator) = 3.23
As a result, you get 3.23 as your answer when you convert 1 89/40 (or 129/40) to a decimal.