A fraction is usually split into two parts: the first part is the number on top, called the numerator; and the second part is the number on the bottom, called the denominator. These are both separated by a line called the “divisor line”. We can use the division method help to solve this question: to get a decimal, simply divide the numerator 131 by the denominator 40 (which you can enter in any calculator):
131 (numerator) ÷ 40 (denominator) = 3.27
And finally, you get 3.27 as your answer when you convert 3 11/40 (or 131/40) to a decimal.